Ma eB Ot ee oar D-w ot tae Ore Oey enn nt de ahaa - e, - shen wyet Ratan poached penedidamarpurevsh ceunattocnetaneattntan ale eben aati tun ieeees wertaeadh aah ar Pere : — ’ ae ; - os ccmanas-unscbeaginosge siiletnairteetnatee a Tanne Samarn . - ae a mean ted seine Anta ; — oe ns hiiinath inns bien nte hate cntneniedeabeidiaiamaniedeaied | een tibaaeiee antl doeskrthesd-aieiivsh tds he eadhindisdataetl - : poe eyes i eases (qqent wad tel nelignboetapeccmwees te endioen eh pwr aetwinitoadnnd ion a-waeeat eames meee era anemae Se LOE It COREL 0 AA ROT BAR AR Ae ea ot Gat gh Ceara arenas HARVARD UNIVERSITY. LIBRARY OF THE MUSEUM OF COMPARATIVE 13.96 ZOOLOGY ee) ame) ¥ ba | Ahh ne Lena ce — JUL 1.61992 | 13,6 : : BU LLETINS AM ERIGANL mak PALEONTOLOGY KX - VOL. XIX. ae, June 70, 1932 fe Harris Co. Ithaca, N.Y. US SecA Price List Bir rae ¢ _ BULLETINS oF AMERICAN » PALEONTOLOGY bit) ey 4 j AND- . PALEONTOGRAPHICA AMERICANA _ BULLETINS OF AMERICAN PALEONTOLOGY. 8v0 Vol. I. 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A. i sl iss mat wit rc ain FOREWORD This paper devoted principally to the Peruvian Miocene con- cludes the series of articles entitled Contributions to the Ter- tiary Paleontology of Northern Peru, of which Parts 1 to 4 dealing with the older Tertiaries have already appeared in these Bulletins. I am deeply indebted to Dr. O. B. Hopkins, Chief Geologist of the International Petroleum Co., for the privilege of publishing and the release of stratigraphic data on Peru as well as his constant encouragement and interest in the work. I wish also to acknowledge the assistance received from the pres- ent and former members of the Geological Staff in Peru, par- ticularly to Mr. A. Iddings, present Manager in Peru and to Mecano Onb wBhoccom) aS Stewant |b Stautt, WillandaBerry, C. W. Boughton, E. Emendorfer, L. W. Wiedey and V. Culbert. In working over the Peruvian collections I have had the ad- vantage of the constant advice of Professor G. D. Harris and the use of the unexcelled collections and library of Tertiary Paleontology at Cornell. During my repeated visits to the Phila- delphia Academy, Drs. H. A. Pilsbry and E. G. Vanatta have most generously extended to me the facilities of the Academy for the study of the collections in their care. I am also grateful to Professor C. Dunbar of Yale University for the privilege of studying the Nelson collection and the loan of valuable type material. In this paper, the following new subgenera and sections are proposed : Illesca new subgenus of Lucina Bruguiere Zorrita new subgenus of Pseudomiltha Fischer Chionopsis new section of Chione Megerle von Muhfeld Hexacorbula new section of Bothrocorbula Gabb Tenwicorbula new subgenus of Corbula Bruguiére Pyrucha new subgenus of Cancellaria Lamarck Perunassa new subgenus of Buccinanops d’Orbigny Fusinosteira new subgenus of Solenosteira Dall Gloversville, N. Y. January 25, 1932. 5 OLssoN: PERUVIAN MI0ocENE 5 CONTENTS 1 REVIEW OF LITERATURE DEALING WITH THE PERUVIAN MIocENE II. THe Miocene oF NortTHerRN PERU 1. THE Zorritos DISTRICT A. The Zorritos Group a. The Lower Zorritos formation b. The Variegated beds e. The Upper Zorritos formation B. The Cardalitos formation C. The Tumbez formation 2. THE SEcHURA DISTRICT III. CoRRELATION AND AGE IV. FauNnaAL AFFINITIES V. Tertiary History oF THE WEsT CoAst oF SouTH AMERICA 1. INTRODUCTION 2. Tuer BoLiIvAR GEOSYNCLINE 3. TERTIARY MOUNTAINS AND CLIMATE VI. SYSTEMATIC DESCRIPTION OF Mt1ocENE MOoLLuSsKS' oF NorTHERN PERU I. A REVIEW OF THE LITERATURE DEALING WITH THE PERUVIAN M1I0CENE AND LATER DEPOSITS The earliest papers dealing with the Peruvian Tertiaries are strictly paleontological, devoted to the description of sma! fossil collections from Paita and Zorritos. The first of these is found in D’Orbigny’s monumental work dealing with his travels and research in South America and includes the description of a few fossil species from the Paita region. D’Orbigny did not person- ally visit any part of the Peruvian coast north of Callao, the fossils from Paita having been collected by Gaudichaud and other travelers. Rostellaria gaudichaudi (=Ectinochilus) (op, cit. p. 116, pl. 14, figs. 6-8) as previously indicated, is an upper Eocene form common in the Saman sandstones while Pectunculus pay- tensis (=P. inaequalis Sby.) (p. 129, pl. 15, figs. 11-13) is com- mon in the Mancora tablazo. Monoceras blainvilli (p. 116, pl. 6. 1D’Orbigny, 1842, Voyage dans VAmérique méridionale., vol. 3, pt. 4, Paléontologie, 1-188 pp. 22 pls. 6 BULLETIN 68 6 fig. 18, 19) described without locality but suspected as being from Paita, was rediscovered in the tablazo beds at Santa Lucia hill near Amotape. Our specimens agree exactly with D’Orbigny’s figure so that there can be no doubt but that Paita is the type locality for this species. Monoceras (Acanthiza) blainvilli has been recorded by Darwin, Hupe, Steinmann and Moricke from the Coquimbo beds of northern Chile and this species is therefore important in the correlation of these rocks with northern Peru. According to Hupe, there are two distinct forms in the Coquimbo beds, the first of which he regarded as typical and a second noded form to which Moricke later gave the varietal name nodosa. The figures given by Philippi included the noded form (var. nodosa Moricke) and a copy of D’Orbigny’s figure of blainvill. Cardium acuticostata (p. 120, pl. 12, figs. 19-22) from Quiriquina is said to occur at Paita on the authority of Brongniart. Since acuticostata was described from a cast, its identification with a Paita shell must be questioned. Venus petitiana (p. 123, pl. 13, figs. 9-11) from Coquimbo, is also re- corded from Paita. D’Orbigny’s figure of this species resembles a Clementia and the Paita record may be based on a specimen of Clementia peruviana Olsson from the Saman_ sandstones. D’Orbigny compares petitiana with Venus dombeyi Lamarck which is a Protothaca and the internal cast figured with petitiana belongs to a thick-shelled species. Philippi who copied D’Orbig- ny’s figure was not able to recognize this species with certainty. A few other species described by D’Orbigny from unknown lo- calities, although associated with Mesozoic forms may prove to be Tertiary species from Peru and Chile. Astarte dubia as in- dicated by Woodring’, is possibly a Clementia but it does not resemble any of the Peruvian species and moreover is described as having a lunule which would remove it from that genus. The Brachyuroid described as Portunus peruvianus is possible an Eocene species. In 1870, Gabb® published the descriptions and later the fig- ?Woodring 1926, American Tertiary mollusks of the genus Clementia. U. S. Geol. Survey Prof. Paper 147, p. 42. °Gabb 1870, Description of new species of South American Tertiary. Am. Jr. Conch., vol. 5, p. 263; 1877, Description of a collection of fossils made by Dr. Antonio Raimondi in Peru, Journ. Acad. Nat. Sci. Phila., 2nd ser., vol. 8, p. 262, pl. 36. a OLSSON: PERUVIAN MrocenE 7 ures of a small collection of Paita fossils submitted by Dr. Antonio Raimondi, supplemented by a few forms obtained by Professor Orton. Of the seventeen species enumerated, ten are considered as new. Only a part of Gabb’s species have been rediscovered and a search of the Academy’s collection at Phila- delphia failed to locate the types of Raimondt’s collection. It is probable that they were returned to Peru after the completion of Gabb’s studies. It is known that Gabb, like D’Orbigny, had fossils both from the Eocene or Saman sandstones and the tab- lazo deposits. Cerithiwm levisculum and Ampullina ortoni are common Upper Eocene species throughout northern Peru. FRaeta gibbosa is probably Gould’s Raeta undulata, a recent West Coast species. Steinmann‘ has figured FR. gibbosa from an internal cast collected in the tablazo beds above Paita. The Raeta is said by Gabb to occur with Volutilithes plicifera, which has not been rediscovered, and Pholas chiloensis Molina, a recent species. Gabb noted the variation in lithological character of the different specimens and suggested that they belonged to two or more dif- ferent eras. One set consisting of a mixture of living and ex- tinct species of similar appearance he considered as Pliocene in age. The first description of Miocene fossils from Peru, was pub- lished in 1870 by E. T. Nelson® in a graduation thesis in the Transactions of the Connecticut Academy of Science. This collection was made by Professor F. H. Bradley and Mr. E. P. Larkin in 1867 at Zorritos. Grzybowski who visited Zorritos in 1898, and Drs. Singewald and van Holst who collected Spieker’s material, obtained only a few of Nelson species and until recently, the exact locality and horizon of most of Nelson’s forms re- mained unknown. In a visit to Zorritos in 1925, I was fortunate in rediscovering most of Nelson’s species in a small block of down-faulted beds exposed near the mouth of Quebrada Tucillal just north of the Zorritos school-house. Since this fossiliferous zone has a very limited development, there can be no doubt but that it is the type locality of Nelson’s species. Fifty-five species of mollusks are recorded by Nelson of which twenty-three are de- 4Steinmann 1929, Geologie von Pert, Heidelberg, p. 257, fig. 261. 5Nelson 1870, On the Molluscan Fauna of the later Tertiary of Peru, Trans. Conn. Acad. Sci., vol. 2, p. 186. 8 BULLETIN 68 8 scribed as new. A few species are identified with recent West Coast forms, while the remainder are referred to their genera only. Only a part of the new species were figured so that until Spieker restudied and refigured the collection, Nelson’s work has been difficult to use and a few of his species have been redescribed by other authors. Nelson’s descriptions are generally good and he carefully compared his specimens with recent forms to which in many cases they are closely related. Spieker’s criticism that Nelson’s paper carries little biologic and no geologic significance is hardly true, as Nelson clearly recognized the close affinities which most of his species had with the recent West Coast fauna thereby proving its late Tertiary age as indicated by the title of the paper. The paleontological papers of D’Orbigny, Gabb and Nelson had proved the occurrence of Tertiary formations in the coast region of northern Peru but aside from the brief description of the Paita cliffs by Orton®, Spruce’s’ notes on the Chira and Piura valleys and the principally geographical writings of Rai- mondi, the geology of this region remained practically unknown until the appearance of Grzybowski’s® account of a geological re- connaissance from Paita to Tumbez in 1899. The geological com- plexity of the Peruvian region was however too great and the small collections of fossils from Paita and Talara not sufficiently diagnostic to permit accurate age determinations and conse- quently Grzybowski in the limited time which he devoted to this reconnaissance failed to obtain a correct idea of the rock suc- cession and the general structure. Grzybowski however proved the extensive development of Tertiary beds in the Peruvian lit- toral and correctly determined the lower Miocene age of the Zorritos formation. Grzybowski’s description of the geology of the Paita region is accompanied by a diagrammatic sketch of the coast and a detailed section of the tablazo cliffs east of the city. To the west of Paita, the coast is formed of Paleozoic phyllites as previously noted by 6Orton, 1871, The Andes and the Amazon, New York, pp. 115, 116. 7Spruce 1863, Notes of a Botanist on the Amazon and Andes, edited by A. R. Wallace 1908, pp. 330-333. 8Grzybowski 1899, Die Tertiirablagerungen des nérdlichen Peru und ihre Molluskenfauna. Beitr. Geol. Pal. Sudamerika, N. Jahrb. Min. ete. BB. 12 pp. 610-644, pls. 15-20. 9 OLSSON: PERUVIAN MIoCENE 9 Orton but apparently Grzybowski did not devote much time to this section as he failed to discover the fossiliferous [Eocene sandstones which occur here, resting on slates and immediately overlain by tablazo deposits. To the east there are high cliffs formed of two series of rocks. In the upper part are sand- stones and conglomerates (a and b) to which Grzybowski gave the name Paita formation. These are the Mancora tablazo de- posits of Bosworth and later writers. Grzybowski referred the Paita “stufe’ to the Pliocene on the basis of its faunal mixture of living and extinct species, in part on the resemblance of cer- tain forms to species from the Coquimbo beds of northern Chile and from Gabb’s earlier determination of a Pliocene age for a part of Raimondi’s collection. These beds overlie unconform- ably a shale series (c) which Grzybowski considered the same as the shales which he later observed at Talara. These shales lying beneath the tablazo beds Grzybowski referred to the Up- per Miocene but they are now known to belong to the Chira formation and of Lower Oligocene age. Five species of mollusks are described as new from the Paita or tablazo beds. Pecten paytensis is a synonym of Pecten ventricosus Sowerby, a recent species. Pecten mtercostatus (renamed P. incus by Hanna and Israelsky ) may be a valid species but has not been rediscovered. Pecten densicinctus is probably ventricosus or a young purpura- tus. Ostrea lunaris is O. prismatica Gray, a recent West Coast species. Ostrea oculata is a large species of the georgiana type and is probably no longer living. Specimens of this large oyster, two feet or more in length are locally common in the tablazo beds near Santa Lucia hill, Talara and elsewhere. The seven species described from the underlying shales are unknown to me. Since ‘these shales belong to the Chira formation, they are of lower Oligocene age. Columbella turrita (renamed C. paytensis by Hanna and Israelsky) from its figure, seems to be Ectinoch- tlus gaudichaudi previously described by D’Orbigny from Paita. The tablazo section at Talara Grzybowski considered similar in age and formation to that observed at Paita. The shales at the base of the cliffs or “stufe c’’ where named the Talara for- mation and correlated with the shales at Paita. The Talara shales are of Eocene age and the name Talara formation has been restricted to the lower Upper Eocene shales and sandstones 10 BULLETIN 68 10 which lie directly above the Upper Eocene unconformity at the Lase of the Discocyclina peruviana zone and below the orbitoidal Verdun sandstones (Saman formation). Six species are record- ed from the Talara shales, five of which are described as new. I have failed to recognize any of these forms. The discussion of the geology of the Zorritos region and the description and illustration of the Miocene fauna are the more important parts of Grzybowski’s paper. Boca Pan, Zorritos and Caleto Grau are separately described, followed by an account of the geology of the Tumbez valley as far as Mangurco. As Grzybowski’s studies on the Zorritos Miocene will be frequent- ly referred to later in this paper, further review of his work is not needed in this place. Douvillé’s? important papers establishing the Eocene age of the rocks at Negritos with the description of several new spe- cies need only be mentioned as they do not contain references to any Miocene forms. Spieker’s'? paper entitled, “The Paleontology of the Zorritos formation of the North Peruvian Oil Fields” is the most ex- tensive report on the Peruvian Miocene which has yet appeared. It is based principally on fossil collections made by Drs. Singe- wald and van Holst in the Zorritos region. A valuable feature of the paper is the re-study and re-figuring of most of the Nelson collection preserved in the Peabody Museum at Yale University. The discussion of the stratigraphy of the Zorritos region is based upon the field studies of van Holst and Singewald and upon the earlier work of Grzybowski. A few mistakes are made principally in the interpretation of Grzybowski’s section at Mal Paso. Spieker subdivided the Zorritos formation into three parts to which he gave the names the Lower Zorritos, the Varie- gated beds and the Upper Zorritos and indicated their physical and faunal characteristics. These are well-marked rock groups and may be easily recognized over a large area in the Zorritos 9Douvillé 1920, L’Eocéne au Perou, Compt. Rend. Acad. Sci. Paris, vol. 171, p. 1345; 1921, Nouveaux fossiles de |’Hocéne du Perou, C. R. som. Soc. Géol. France, pp. 193-195; 1921, Mélanges paléontologiques, Journ. Conchyl. vol. 66, pp. 1-18, 2 pls., 4 figs. 10Spieker 1922, The Paleontology of the Zorritos Formation of the North Peruvian Oil Fields, The Johns Hopkins University, Studies in Geolo- gy, No. 38. il OLSSon: PERUVIAN M1ocENE 11 district. Unfortunately Spieker makes the mistake in consider- ing the section measured by Grzybowski at Mal Paso which he copies as belonging to the Zorritos group. The upper part of this section, or beds a to c belong to the Tumbez formation of Upper Miocene age and not to the Upper Zorritos sandstones as believed by Spieker. Beds c fo 1 which Grzybowski consid- ered as Heath is a faulted section with part of the beds missing. These rocks were considered as Variegated by Spieker. They actually belong to the upper and lower part of the Cardalitos shales. Spieker discusses one-hundred and one species or varieties of mollusks of which sixty-one are described as new, or renamed. All these forms are considered as belonging to the Zorritos for- mation although most of Nelson’s species are now known to be much younger in age as well as the few species belonging to the Cardalitos shales. This mixture of Lower Miocene species such as the group of Arca (Seniia) chiriqiuensis Gabb with such Upper Miocene forms as Dosimia grandis Nelson is responsible for the Middle Miocene appearance of the fauna noted by Woodring. In the treatment of certain genera such as the Turritella, Arca and Raeta, Spieker has excessively multiplied the number of new species and subspecies which cannot be sep- arated in a larger collection. In an effort to determine the age of the Zorritos formation, most of the fossils are compared with European and other foreign species while their affinities with recent forms is usually lost sight of. Many Zorritos species and particularly those from the Nelson collection are very closely related to species now living along the West Coast while their indicated relationship with European types is extremely doubtful and of no great significance. Dosimia grandis Nelson is com- pared with D. orbicularis Agassiz of the Miocene of the Vienna basin and is said to have no closely similar American species but as pointed out by Nelson, D. grandis is very near D. ponder- osa Gray ranging from Lower California to Paita and has even been figured as fossil from the Coquimbo beds of Chile by Philippi. Discussing Twurritella alturana Spieker (T. plana Nelson) comparison is made with several Eocene species par- ticularly 7. dickersont Anderson from California but as may be seen from the growth-lines, the Peruvian form has no relation- 12 BULLETIN 68 12 ship with these Eocene species but is simply a fossil subspecies of T. broderipiana d’Orbigny of the recent Panama fauna. With few exceptions, the Zorritos fauna is not well-preserved and its study is therefore more difficult than is the case with the beau- tifully preserved Miocene mollusks of the Caribbean region. On the whole therefore, Spieker’s' study is an earnest effort in de- scribing and illustrating the Zorritos fauna and his conclusion regarding the age of the Zorritos formation is essentially cor- nec: Bosworth’s'! comprehensive book on the Geology of northern Peru, appeared about the same time as Spieker’s work on the Zorritos formation. It deals however more particularly with the older Tertiary and Quarternary deposits centering about Negri- tos while the geology of the Miocene beds of Zorritos is only briefly touched upon. Nine Miocene species are mentioned and figured by Woods of which two are considered as new species. Woods Crassatellites charanensis is a large specimen of Grzybowski’s Eucrassatella nelsoni. Professor Berry’ has contributed several papers dealing with fossil plants from the Tertiaries of northern Peru. The first contribution is devoted to the description of a collection of fossil leaves made in 1875 by C. F. Winslow. The locality of these plant-beds is stated as being about twenty miles south of the town and river of Tumbez and 200 to 300 feet inland from the shores of the Pacific. Professor Berry correctly identifies this locality with the lignitiferous shales mentioned by Grzybowski in his section at Mal Paso. Following Grzybowski, these plant beds are regarded as belonging to the Heath stage while their asso- ciation with oyster beds as previously noted, lead Spieker to refer them to the Variegated. These plant-bearing shales associated with a seam of coal belong near the base of the Cardalitos shales or just above the upper Zorritos sandstones and this zone may be traced inland for more than a mile to the banks of Quebrada 11Bosworth 1922, Geology of the Tertiary and Quarternary period of North-West Peru, with an account of the Paleontology by H. Woods, T. W. Vaughan, J. A. Cushman and others. 12Berry 1919, Miocene fossil plants from Northern Peru, Proc. U. S. Nat. Mus., vol. 55, pp. 279-294, pls. 14-17. 13 OLSSON: PERUVIAN MI0CENE 13 Charan. On basis of stratigraphy and other considerations, the age of this florule appears to be lower Middle Miocene or ap- proximately equivalent to the Lower Gatun of the Canal Zone. One species Guatteria culebrensis Berry is known from Gatun and Culebra beds of the Canal Zone while Tapira lanceolata Inglehardt is recorded from Loja. Persea macrophylloides I'nglehardt, questionably identified, is found in the Navidad beds of Chile and in Colombia. The Loja flora first described in 1895 by Engelhardt, has usually been considered at Lower Miocene. A recent study of new collections from this locality has been made by Berry who concludes that the Loja flora be- longs to the late Miocene. A second paper by Professor Berry" records the occurrence of Miocene rocks in the Santa Elena peninsula of western Ecuador and the extension of the Zorritos formation into the Chira valley. There are no Miocene rocks in the Chira region and the supposed Zorritos species from Casa Saman are Upper Eocene species belonging to the Saman for- mation. Several Saman species such as Clementia peruviana and certain of the Turritellas have an Upper Tertiary aspect and are easily mistaken for Miocene species. The other papers of Pro- fessor Berry and Willard Berry deal with the older beds and need not be discussed in this review. A small collection of fossils obtained by Messrs eae Burtt and May during geological reconnaissance trips in northern Peru and deposited in the California Academy of Science, were de- scribed in a paper by Hanna and Israelsky"*. Fourteen species are considered of which eleven are described as new. Turritella conquistadorana, Melanatria (?) gesteri (=Hannatoma), Cla- vilithes burttt (=Mancorus) and “Surcula’ mayi are Oligocene species. Five Miocene species are considered as new, two of which namely Crassatellites pizarroi and Clavilithes (?) atahual- pai are synonymous with Eucrassatella nelsoni Grzybowski and 13Berry 1923, Extension of Miocene Zorritos Formation in Peru and Ecua- dor, Pan-American Geologist, vol. 40, pp. 15-18. 14Hanna and Israelsky 1925, Contribution to the Tertiary Paleontology of Peru, Proc. Calif. Acad. Sci., 4th series, vol. 14, No. 2, pp. 37-75, pls. 7, 8. 14 BULLETIN 68 14 Northia “Struthiolaria”’ guttifera Grzybowski. This paper also contains a check list of Peruvian Tertiary species described up to 1925 and the names of nine species having been found pre- occupied, are changed. The practice of renaming species pre- occupied by older names, without knowledge of the species in question is open to criticism as it frequently leads to an unneces- sary multiplication of names and much confusion to later work- ers. Thus Turritella robusta Grzybowski is renamed supracon- cava although as pointed out by Woodring there are at least three earlier names available for this species. Arca retractata Hanna and Israelsky (=A. modesta Grzybowski) may eventu- ally prove to be the same as Arca macdonald: Dall from Costa Rica but common in the Miocene rocks of northern Colombia, Venezuela and Trinidad. Columbella paytensis (=C. turrita Grzybowski) is probably Ectinochilus gaudichaudi d’Orbigny but as previously noted most of Grzybowski’s Paita and Talara species have not been rediscovered and their status must await study of the type specimens. A short paper on the Geology of the Illescas region and in- cluding an areal geologic map of this part of the Sechura desert was published by A. Werenfels*® in 1927. The general geology of this region is well described but unfortunately apparently due to mixed fossil collections or wrong paleontological determina- tions, the age and correlation of the different formations are poorly understood and consequently the stratigraphic section given by Werenfels requires considerable revision. The follow- ing table shows the changes necessary : 15Werenfels 1927, Geology of the Illescas Region, Northern Peru (South America). Eclogae Geologicae Helvetiae vol. 20, No. 4. pp 473-486, plea 15 Werenfels, 1927. Montera formation as Upper Eocene OLSSON: PERUVIAN MIOCENE Iddings and Olsson Correct age Sechura formation Pliocene 15 unconformity Yapate sandstone 4 Salina beds of Zodiac Pt. as Diatomaceous Lower and Middle Hocene Amarilla ss. Yapate sandstone of Trice Trac Pt. as Middle Eocene earth and shales Middle Miocene Bayovar beds as lower Hocene Not recognized Charaos sandstone Montera formation (break in section through faulting) Bayovar formation Lower Miocene Saman formation Lower Oligocene Upper Upper Eocene Talara formation Lower Upper Upper Eocene (Olsson 1930) Eocene The Charaos formation, (p. 483) named from Charaos Non- ura Bay, are the oldest Tertiary rocks in this region and not the youngest as believed by Werenfels. They contain a fauna principally of small Orbitoids which in many cases are so abun- dant as to form a foraminiferal limestone. At several places where these flat-lying foraminiferal limestones rest upon slates or other mountain rocks, they simulate to a remarkable degree, tablazo deposits and the Maxiplan of Werenfels (elevation 390 feet) south of Bayovar, represent these Eocene limestones and not a true tablazo level. Werenfels lists Asterodiscus along with Heli- colepina and small Lepidocycline which places these beds about equivalent to the Talara formation of the Negritos region. The Charaos formation is also found along the northeast side of the Cerros de Illescas but they are not equivalent to Werenfels’ Montera formation capping Corona hill which is of Pliocene age. Small remnants of the Charaos formation have been found capping a few of the mountain peaks within the Cerros de Illescas at elevations of 1200 to 1300 feet. 16 BULLETIN 68 16 The Bayovar beds occur only in the cliff sections extending from Bayovar to Tric Trac Point. Werenfels regarded these foraminiferal shales as the oldest Tertiary deposits occuring in the Sechura region and referred them to the Lower Negritos formation or the Lower Eocene. Although the contact is not visible, the Bayovar beds apparently rest upon the Saman sand- stones which occur just northwest of Bayovar and are of Lower Oligocene age. East of Tric Trac Point and along Quebrada Montera, there are excellent exposures of Miocene sandstones to which Iddings and Olsson referred in 1928, as the Montera formation. The Mio- cene age of these rocks is incontestable although Werenfels lists V enericardia planicosta, Ostrea Buski, Meretrix Bosworth, etc., from the Amarillas sandstones which are evidently the same beds. For a complete list of the fossils of the Montera formation, the reader is referred to the later pages of this paper. The Eocene forms listed by Werenfels could not have been collected in the Amarillas sandstones or else they are incorrectly determined Miocene species. The Yapate sandstones of Tric Trac Point and the Amarillas sandstones belong to the Lower Miocene and not to the Middle Eocene as indicated by Werenfels. Exposures of diatomaceous earth occur around the borders of the large salt basin and along the cliff front near Yapate and elsewhere. These deposits are clearly younger than the lower Miocene sandstones of Quebrada Montera and Tric Trac and are provisionally referred to the Middle Miocene. In a separate paper, Werenfels'® described these occurrences of diatomaceous earth as belonging to the Eocene although he pointed out that commonest diatom was identical with Coscinodiscus oculus iridis Ihrenberg of the Monterey Shales of California. The Montera formation capping Corona Hill is a whitish, arenaceous limestone, often conglomeritic and rests unconform-— ably on the underlying Miocene or even overlaps to a slight ex- tent upon the Illescas slates. It contains no Orbitoids so abundant in the Charaos (which Werenfels correlated with the Montera beds) but such species as large Macrocallista and Dosinia grandis 16Werenfels 1926, Diatomeenerde im Eocin von Pert. Eclog. geolog. Helvetiae vol. 19, pp. 630-631. 17 OLSSON: PERUVIAN MrocENE 17 Nelson show its late Miocene or Pliocene age. It is believed to be a coastal facies of the Sechura formation and of Pliocene age. Marsters’'’ papers which deal in part with the Zorritos dis- trict are very general in scope and have no paleontological nor stratigraphic value. Deustua and Quiroga’® have also described the geology of the Zorritos region, in their papers dealing with the petroleum resources of Peru. Steinmann’ in his Geologie von Peru, gives a short description of the Zorritos formation based principally on Spieker. Steinmann following Grzybowski still places the Talara formation in the upper Tertiaries. Twurri- tella infracarinata Grzybowski from the Miocene of Bayovar is figured so that Steinmann recognized the Miocene character of the rocks in this district. The only other paper which need be considered in this re- view, is that of Iddings and Olsson?° published in 1928. This paper gives a general account of the geology and stratigraphy of the entire Tertiary region of northern Peru from the Sechura desert north to Tumbez. It proved the remarkable completeness of the Peruvian Tertiaries from the Lower Eocene to the Upper Miocene. For the Miocene rocks, two new formational terms were introduced, namely the Cardalitos and Tumbez which had not been recognized before. Reference to this paper will be fre- quent in the course of the following pages. Il. THe Miocene oF NorTHERN PERU Marine deposits of Miocene age occur in northern Peru in two separate districts. The most important are those of the Zorritos- Tumbez region and represent the extension of a Miocene em- bayment south from the Guayas district of Ecuador. This northern embayment did not extend beyond Piedra Redonda. 17Marsters 1921, Outline of the Geology and Development of the Pe- troleum fields of Peru, with notes on other occurrences in the Peru- vian Republic. Bull. Am. Ass. Petroleum Geologists, vol. 5, pp. 585-604. IsSQuiroga 1925, Sintesis de la Mineria Peruana, Ministerio de Fomento, tomo. 2, la parte, Yacimientos Petroliferos. 19Steimann 1929, Geologie von Peru, Heidelberg, p. 199. 20Iddings and Olsson 1928, Geology of Northwest Peru, Bull. Am. Ass. Petroleum Geologists, vol. 12, No. 1, pp. 1-39. 18 BULLETIN 68 18 The second district is found in the Sechura desert and in its turn marks the northern end of a Miocene sedimentary basin which probably at that time extended southward off the Peru- vian coast and connected with the Miocene belt of the Paracas Peninsular. No Miocene rocks occur in the intervening region and consequently only indirect communication existed between these two areas of Miocene sedimentation. Several! Caribbean types of mollusks are found in the Sechura Miocene and in a sim- ilar way certain Zorritos forms such as Buccinanops (Perunassa) zorritensis Nelson and Chorus solida Nelson are probably of southern origin. Aside from this intermingling, the Peruvian Miocene clearly belongs to two separate faunal provinces, the northern or that of Zorritos being warm-water and distinctly Caribbean in character while the southern or that of the Sechura and Paracas belongs to a cooler-water type’ as shown by the ex- tensive development of diatomaceous earth and its fauna is prob- ably in large part of South Pacific origin as the Peruvian fauna south of Negritos and Punta Parinas is to-day. Fuller knowl- edge of the Sechura Miocene and that of southern Peru would undoubtedly reveal a greater faunal likeness with the Chilian Miocene than now appears to be the case. THE Zorritos DistTrict Nelson’s strictly paleontological study of a collection of Zorri- tos fossils had indicated the presence of late Tertiary rocks at Zorritos but it remained for Grzybowski to definitely establish the extensive development of Miocene strata in that district. Bosworth also collected a few Miocene species of mollusks at Zorritos which were studied by Woods. Bosworth referred all the Miocene rocks of northern Peru to one group which he called the Zorritos formation and on his map shows these rocks as ex- tending as far south as Punta Sal, thus covering the outcrop of the Punta Bravo grits which are now known to be Middle Oligo- cene in age. Spieker also regarded the Zorritos Miocene as rep- resenting a single formation which he however divided into three members, the Upper and Lower Zorritos sandstones and the Variegated beds. In 1928, Iddings and Olsson divided the Zor- 19 OLSSON: PERUVIAN MI0cENE 19 ritos beds into three formations as follows: Upper Miocene Tumbez formation Middle Miocene Cardalitos formation Lower Miocene Zorritos formation As Spieker found, the Variegated beds and the Upper Zor- ritos sandstones are closely related while greater faunal differ- ence exist between these rocks and the Lower Zorritos. The re- sults of our own studies have indicated that on faunal as well as stratigraphic grounds, the Lower and Upper Zorritos sandstones should be considered as separate formations. Together, the Lower and Upper Zorritos formations make up the Zorritos group. The Zorritos and Tumbez sandstones and conglomerates form a rugged, hilly topography and a sandy soil supporting a growth of small trees (Palo Santos Bursera graveolens, Hualtaco Lo«- opteryguum huasango) and bushes while inland where precipita- tion is greater almost impregnable thickets of Unas de gato are frequent. Many of these Miocene hills rise to commanding heights. Hills formed of the Zorritos sandstones include Cueva de Leona, Pan de Azucar and Salvajal while La Garita, Tucillal and Cerro Bruno are composed in whole or in part of the Tum- bez beds. From the soft, easily weathering shales of the Carda- litos formation, a dense clay soil is formed, and a subdued topog- raphy of low, rolling hills. In the dry seasons these shale areas become dried and parched to an extreme degree but after rain are converted into meadows of tall grasses, leguminous plants and vines. From Piedra Redonda, the Zorritos sandstones overlying the Heath shales strike northeast, crossing Quebrada Boca Pan at Zapotal just south of Vacura. East of Boca Pan, the Zorritos sandstones form the hills of Pan de Azucar. Somewhat further south and east are the hills of Animas and Salvajal separated from the Pan de Azucar ridge by faulting so that the intervening area belongs to the Heath shales. From Animas, the Zorritos sandstones extend east to the Tumbez river, gradually overlap- ping the older beds so that first the Heath shales, then the Punta 3ravo grits disappear beneath the blanket of Miocene sediments until at Rica Playa, the Zorritos sandstones rest directly upon 20 BULLETIN 68 20 granite and Eocene formations. At Zapotal, the Lower Zorritos sandstones are conformable and transitional with the Heath shales but in the Tumbez district, the transgressive character of the Zorritos is unmistakable. Conditions east of the Tumbez river are not known. As further south at Lobitos and Negritos, the rocks of the Zorritos region, particularly along the coast, have been intense- ly faulted. These are normal or gravity faults and they have developed a complicated series of irregularly-shaped fault blocks of greater or less size. At Tumbez and in the region inland from Zorritos, the strata usually dip to the northwest so that in general older beds are encountered on approaching the foot of the Amo- tape mountains. Faults trend in various directions but the most persistent and probably the youngest are large strike faults trending roughly parallel to the coast. These faults may be downfaulted either on the north or south side. THE ZorRITOS GROUP The name, the Zorritos formation or Zorritos stufe was given by Grzybowski*' to the fossiliferous yellow sandstones which lie above the Heath shales in the Zorritos district, the type section being the exposures near Zorritos village and Boca Pan. From Zorritos, Grzybowski listed the following species: Arca Larkinti Nelson = A. chiriquiensis toroensis Spicker ‘¢ septifera Grzybowski eis (Noetia) modesta Grzy. = A. retractata Hanna and Israelsky Psammobia Darwini Phil. Venericardia clavidens Grzy. Turritella rotundata Grzy.= T. infracarinata Grzy. re Infracarinata Grzy. Inca Grzy. gothica Grzy. = T. bifastigata Nelson inconspicua Grzy. robusta Grzy. = T. abrupta Spieker Gabbiana Grzy. = T. filicincta Grzy. Solarium sealineatum Nelson. = Architectonica Struthiolaria guttifera Grzy. = Northia Venericardia clavidens is an Eocene species from Rica Playa and was no doubt listed from Zorritos by mistake. Psammobia Darwini is a Tageloid and its identification with a Chilian species °1Grzybowski 1899, op. cit., p. 652. 21 OLSSON: PERUVIAN MIOCENE 21 must be questioned while Arca Larkinii Nelson is probably not this species but A. chiriquiensis toroensis Spieker. Turritella gabbiana appears to be a synonym of filicincta which is usually a Cardalitos species. With exception of these changes, the rest of Gzybowski’s species are common forms in the Upper Zorritos formation as here understood. At Zorritos and Boca Pan, the Zorritos group may be divided as Spieker has shown into three parts. The Lower and Upper Zorritos formations are principally massive to well-bedded, soft or hard, yellow or orange-colored sandstones and pebble con- glomerates. They are locally fossiliferous. Between these pre- dominately yellowish sandstones there is a middle member which Spieker called the Variegated beds. These deposits are particu- larly well developed between Punta Picos and the village of Boca Pan and along the west shore of Caleta Grau near Quebrada Tijeretas. The name of Variegated beds aptly describes their makeup and appearance. They consist of red, green, yellow to chocolate-colored shales interbedded with rust-colored sand- stones, white grits, cobble conglomerates and lignites. Seams of rather pure cannel coal may be present while fossil layers are frequent. As a rule the marine mollusks are worn. Brackish water forms such as Potamuides, oysters and varieties of Arca chiriquiensis are rather characteristic. The Variegated beds are always more badly broken than the Lower and Upper Zorritos sandstones. This intense deformation does not appear to have a great structural significance but is probably due in large de- gree to intraformational creep and surface slumping. When wet the Variegated beds become very soft and treacherous and dur- ing the irregular rainy seasons they suffer greatly from slides and slumping. The Zorritos rocks are here considered as a group since they are generally closely associated in the field. a. The Lower Zorritos formation. Considerable faunal dif- ference exist between the Lower and Upper Zorritos and on stratigraphic as well as faunal grounds, they should be consid- ered as separate formations. The Lower Zorritos formation is the closing stage of the Heath transgression and these rocks were generally laid down in a shallowing sea which reached its greatest restriction during the deposition of the Variegated beds. 22 BULLETIN 68 22 The Lower Zorritos is therefore stratigraphically related to the Heath and in the Zapotal section, the two series of beds are con- formable, the lower Zorritos sandstones passing into the Heath shales. At Piedra Redonda on the other hand, the Zorritos rocks are disconformable on the Heath shales and part of the Lower Zorritos formation appears to be missing. Due to an eastward shift of the Miocene trough which will be discussed more fully in the later pages of this paper, the Lower Zorritos formation is transgressive east of the Boca Pan valley. Except at a few places along Quebrada Higueron near Rica Playa in the Tumbez district, the Lower Zorritos fauna is prin- cipally known from the transitional beds at the base of the Zor- ritos sandstones. The most important locality for this horizon is Zapotal in the Boca Pan valley.. The fossils are generally poorly preserved due to alteration to gypsum, and many species cannot be identified. A small but well preserved fauna was col- lected from this horizon in Quebrada La Cruz north of Mal Paso and about four miles inland. Near Rica Playa, the Lower Zorritos sandstones rest upon granite and Eocene formations and at several places along Quebrada Higueron they are fossil- iferous. In the following list about 59 species are recorded from the Lower Zorritos formation but only such forms which are defi- nitely known to occur in these beds have been included. As Spieker did not recognize the Cardalitos shales as being distinct from the Heath he included such species as Eucrassatella nelsoni Grzy. and Turritella filicincta Grzy. in the Lower Zorritos but they are now known to be strictly Cardalitos forms. Solenosteira alternata Nelson, a Tumber species, was also listed by Spieker from the Lower Zorritos. About 44 species in this tabulation appear to be restricted to this formation or approximately 74.5%. This large percentage of forms as yet not known from other horizons is due in part to our insufficient knowledge of the Heath fauna in its shallow- water facies, there being only 5 species or 8.4% which are known from the older rocks. Only 10 species or 17% pass upward into the Upper Zorritos or younger beds. Doubtless as the Up- per Zorritos fauna becomes better known, this percentage or 23 OLSSON: PERUVIAN MIocENE 23, ratio will be somewhat changed but future discoveries can be expected to add new species to the Upper Zorritos fauna as weil as to extend the range of old ones. It is believed that the ratio of species common to the Lower and Upper Zorritos will remain small but through the extension of certain species down into the Upper Heath, the number of geologically short-lived species in the Lower Zorritos fauna will be reduced to a greater degree. The following species are known from the Lower Zorritos for- mation ; those restricted to this formation are indicated by a *. *Terebra (Strioterebrum) herviderana Spieker *Terebra (Strioterebrum) ulloa Spieker *“Terebra (Strioterebrum) pavonia Olsson *Terebra (Stroterebrum) zapotalensis Olsson Polystira sp. ? in the Chira shales. *Turricula (Pleurofusia) cruziana Olsson *Conus (Leptoconus) sp. *Conus (Leptoconus) multiliratus spiekeri Olsson *Conus (Leptoconus) sophus Olsson Conus (Dendroconus) bravov Spieker. U. Z., Card. Sechura. Cancellaria (Aphera) peruana Nelson. 'Tumbez Cancellaria (Cancellaria) ef. rowelli Dall. Sechura Olivancillaria (Agaronia) dotapaxi Olsson. Posorja *Olivella (Callinanax) tapira Olsson *Pseudolatirus tumbezensis Olsson *Tritiaria peruviana Olsson *Tritiaria cieza Olsson *Phos (Antillophos) woodringi Olsson *Phos (Antillophos?) hodsoni Olsson *Phos (?) latirugatus Spieker *Strombina (Strombina) tumbezia Olsson Acanthiza (Chorus) sula cruziana Olsson. Caleto Mero, Posorja Melongena melongena consors Sby. Var., U. Z. *Distorsio decussatus ringens Phil. Pyrula peruviana Spieker. Card *Cypraea angustirima Spieker *Turritella prenuncia Spieker *Turritella prenuncia cruziana Olsson *Turritella fica Olsson *Natica (Naticarws) sp. Polinices (Neverita) quwirosana F. Hodson. Manecora and Chira forms *Sinum carolanum Spieker *Architectonica sealinearis corusca Olsson. Sechura *Arca (Diluvarca) vanholsti Spieker *Arca (Diluvarca) spiekert Olsson. U. Z. *Arca (Diluvarca) zapotalensis Spieker *Arca (Diluvarea) fissicosta Spieker *Arca (Diluvarca) singewaldi Spieker Arca (Noetia) retractata Hanna and Israelsky, U. Z., Var. *Arca (Cunearca) thalia Olsson 24 BULLETIN 68 24 *“Kucrassatella berryi Spieker “Phacoides insleyi Spieker “Codakia sp. *“Cardium (Trachycardium) gorritense Spieker *“Cardium (Trigoniocardium) hannai Olsson Dosinia (Dosinidea) delicatissima Brown and Pilsbry. U. Z., Card. Heua:- dor Clementia dariena Conrad Transennella herviderana Spieker. U. Z. Macrocallista helenae Spieker. Var. *“Pitaria (Pitaria) sapotana Olsson *“Pitaria (Lamelliconcha) petersoni Olsson *Chione (Chionopsis) propinqua Spieker *“Chione (Lirophora) cf. hendersoni Dall Tellina (Hurytellina) aequicincta Spieker, U. Z. *“Macoma zapotalensis Spieker *Corbula (———————) prenwncia Spieker *Corbula (Hexacorbula) cruziana Olsson *Corbula (Caryocorbula) bravoana Spieker *Corbula (Caryocorbula) fabiformis Spieker The five species in the Lower Zorritos fauna which occur in the older beds are all gastropods. Polinices qwrosana original- ly described by Hodson from Oligocene-Miocene beds of Vene- zuela is found in the Chira and Mancora formations. Polystira sp. may be the same as a Chira shale form in our collection. Oliwancillaria cotapaxi Olsson is known from the lower Upper Oligocene of Ecuador. Acanthiza sula crugiana Olsson is very near typical swla from the Caleto Mero shales and from Posorja IXcuador. Of the ten species which extend into the overlying younger rocks, four are gastropoda and six pelcypoda. Conus bravoi, Melongena melongena consors, Arca spiekeri, retracatata, Dosinia delicatissima, Clement.a dariena, Transenella herviderana and Tellina aequicincta are Upper Zorritos forms. Species ex- tending into the Cardalitos include, Conus bravoi, Pyrula peru- viana while Clementia dariena and Cancellaria peruvana con- tinue into the Tumbez. b. The Variegated beds—The Variegated beds because of their brilliant and varied coloration as well as their intense de- formation are the most striking and easily recognizable of the Miocene rocks in the Zorritos district. Although partly sub- aerial in origin, fossil layers are not uncommon in which may be found a mixture of marine littoral species and brackish-water forms. Oyster zones are common but these fossils are always ~t 25 OLSSON: PERUVIAN MIocENE 2: so badly worn and broken that it has not been possible to deter- mine to what species the Variegated oyster belongs. Aside from oyster fragments, Arca chiriquiensis toroensis and Anomia berryi are the commonest forms in the Variegated beds. The following list includes only the species that are definitely known to belong to the Variegated fauna: Conus (Dendroconus) bravoi Spieker, L. Z., U. Z., Card., Sechura Conus (Dendroconus) ef. williamgabbi Maury. Sechura. U, Z. Northia guttifera Gray. U. Z., Card. *Melongena colombiana Weisbord. Also Colombia Melongena melongena consors Sby. L. Z., U. Z. Turritella varicosta Spieker. U. Z. Turritella et. infracarinata Gray. U. Z. Polinices (Polinices) coronis Hanna and Israelsky, Sechura Calytraea sp. Crepidula sp. *Potamides bocapanensis Olsson Potamides ormei infraliratus Spieker, U. Z. Cerithium infranodaium Spieker. U. Z. Cerithium grillanum Spieker. U. Z. Ostrea sp. Mytilus Anomia berryi Spieker. Sechura, U. Z. Arca (Senilia) chiriquiensis toroensis Spieker, U. Z. Arca (Noetia) retractata Hanna and Israelsky. U. Z., L. Z. Arca (Noetia) cholana Spieker *Chione (Chionopsis) costaricensis Olsson Macoma sp. Labiosa (Raeta) undulata gardenere Spieker. U. Z. Corbula (Caryocorbale) propinqua Spieker The close relationship of the Variegated fauna to the Upper Zorritos is clearly evident in the above list. Of the 19 specitficial- ly determined forms, 12 are known in the Upper Zorritos forma- tion, while only 3 occur in the Lower Zorritos. The few species which appear to be limited to this formation such as Arca cho- lana, Chione costaricensis and Corbula propinqua are rare forms known only from single specimens. Exception to this rule is Melongena colombiana which is fairly common in beds believed to be Variegated in the Tumbez valley. The Upper Zorritos formation.—The Upper Zorritos forma- tion consists principally of yellow or orange-colored sandstones and pebble conglomerates similar in appearance to the Lower Zorritos but easily distinguished by their stratigraphic position 26 - BULLETIN 68 26 above the Variegated beds. At the top, the Upper Zorritos for- mation is a concretionary sandstone which Spieker calls the Cannonball sandstone, a field name of Singewald and van Holst. These large concretions weathering from the cliffs of Piedra Redonda suggested the name of this headland on the north side of Caleto Mero. North of Piedra Redonda, the Cannonball sandstones may be seen dipping beneath the Cardalitos shales. The Upper Zorritos sandstones have an extensive outcrop and form many of the higher hills of the Zorritos region. The ridge of Punta Picos and Cueva de la Leona is principally formed by the harder layers of this formation, the lower southern slopes of these hills being made up of the slumped beds of the Variegated member. The Upper Zorritos sandstones are important at Zorritos, forming most of the hills south of the village. At Zor- ritos, the cliffs along the shore belong principally to the Tumbez formation while the Upper Zorritos sandstones are the surface formation inland. Together with the Cardalitos shales and the Variegated beds, the Upper Zorritos formation borders the shores of Caleto Grau passing inland at Mal Paso. Fossils are common in the Upper Zorritos formation, the prin- cipal forms present being several species of Arca and Turritella. Usually fossils can be collected only on the surface where they have lain exposed to sun and wind and are therefore generally broken and more or less worn. Due to these circumstances, the smaller mollusks which usually bulk so large in the Miocene faunas of the Caribbean region are practically unknown. Species recorded from the Upper Zorritos formation: Ostrea sp. Mytilus sp. Arca (Senilia) chiriquiensis toroensis Spieker, Var. *Arca (Senilia) chiriquiensis septifera Grzy. *Arca (Senilia) zorritosensis Woods Arca (Noetia) retractata Hanna and Israelsky. lL. Z., Var. *Arca (Diluvarca) sechurana Olsson. Sechura Arca (Diluvarca) spiekeri Olsson. Li. Z. *Cardium (Dinocardium) ecuadorialis Olsson. Ecuador *Chione (Chionopsis) spiekerit Olsson. Sechura and EKeuador *Pitaria (Lamelliconcha) aequicincta Spieker Clementia dariena Conrad. L. Z., Tumbez, Sechura Dosinia delicatissima Brown and Pilsbry. L. Z. Card. Pull OLSSON: PERUVIAN M10cENE 27 Macoma sp. Tellina (Hurytellina) aequicincta Spieker. L. Z. “Semele lacvis costaricensis Olsson. Subspecies of recent form Mactrella exoleta Gray. Recent species Labiosa (Raeta) undulata gardnere Spieker. Recent *“Corbula (Tenuicorbula) acutirostra Spieker *Corbula (Tenuicorbula) acutirostra zorritensis Olsson Cancellaria sp. Conus (Dendroconus) bravoi Spieker, L. Z,, Card., Sechura Conus (Dendroconus) ef. williamgabbi Maury. Var., Sechura Northia guttifera Grzy. Card., Var. Melongena melongena consors Sby. L. Z., Var. Crucibulum inerme Nelson. Tumbez Turritella infracarinata Grzy. Var., Sechura., Card. Lurritella imconspicua Grzy. Lurritella varicosta Spieker. Var. Turritella abrupta Spieker. Card. B. THE CARDALITOS FORMATION This name was given in a formational sense by Iddings and Olsson for the black shales which lie above the Upper Zorritos sandstones. Their type exposures are found along Quebrada Cardalitos between Piedra Redonda and Punta Picos. Spieker referred these shales to the Talara (op. cit. p. g) accepting Grzybowski’s view that the Talara shales belonged to the Upper Miocene. This point has been discussed in an earlier part of this paper. Lithologically, the Cardalitos shales are very similar to the Heath and they are best differentiated by their stratigraphic re- lations to the Zorritos and Tumbez sandstones. Just south of Punta Picos, the Cardalitos shales may be seen resting normally on the Cannonball sandstones of the Upper Zorritos while to the south and east of Zorritos, numerous sections show the Cardalitos shales lying beneath the Tumbez sandstones. The Cardalitos shales when fresh are black in color and strongly bituminous but weather like the Heath and Chira shales to a dark chocolate color or a dull gray. In some sections there are bands of fullers earth and zones of small, yellow concretions. In the Mal Paso area, the basal Cardalitos shales are strongly lignitic with one or more seams of coal and bands of oysters. Grzybowski failed to recognize faulting at Mal Paso and he therefore placed these lignitic beds as lying directly below the Tumbez sandstones which form the high cliffs of Mal Paso but actually this horizon occurs just above the Upper Zorritos sandstones. This section was 28 BULLETIN 68 28 copied by Spieker who referred the Tumbez sandstones of Mal Paso to the Upper Zorritos and the lignites and oyster beds of the basal Cardalitos to the Variegated beds. It was from these lignitic shales that Winslow collected the fossil leaves later de- scribed by Professor Berry. The outcrop of the Cardalitos formation is rather extensive. The most southerly exposures are found along Quebrada Car- dalitos and to the southeast of Quebrada Picos. A small patch of the Cardalitos shales often mapped by geologists as Heath, occurs at Sechurita where these shales may be seen passing be- neath the Tumbez sandstones at the mouth of Quebrada Grillo while to the south they lie in fault contact with the Variegated beds and the Upper Zorritos formation. At Mal Paso, the Tumbez sandstones overlie a small thickness of very fossiliferous Cardalitos shales. On the south, faulting has brought up the top of the Upper Zorritos sandstones overlain by the lower Car- dalitos with lignites and oyster beds. Much larger areas of Cardalitos shales are found along Quebrada Zapotal and its tributaries lying to the north of the Zorritos sandstone hills of Pan de Azucar and south of the Lower Zorritos exposures of Hervideras and the hills along the sources of Quebrada Grillo and Tucillal. Other important outcrops of the Cardalitos shales occur in the upper part of Quebrada Heath and Quebrada Tucil- lal underlying the Tumbez sandstones of Cerro Bruno and Tucillal. The upper Cardalitos shales, in particular the transitional beds passing into the Tumbez sandstones are often fossiliferous and most of the mollusks known from this formation belong to this horizon. This zone is well developed at the base of the sand- stones of Mal Paso but at this place fossils are generally diffi- cult to extract from their matrix. The same zone occurs below the Tumbez sandstones of Cerro Bruno and fossils from this horizon particularly Eucrassatella nelsom and Turritella altilira have been distributed the whole length of Quebrada Heath by flood waters. A fossiliferous bed at approximately the same stratigraphic level is found at Sechurita near the mouth of Que- brada Grillo and has yielded several interesting species. Some- what lower in the Cardalitos shales is the zone of Pseudomultha 29 OLSSON: PERUVIAN MIOCENE 29 (Zorrita) petersoni and smaller Corbulae. The zone of Pseudo- miultha has also been found in Cerro Tucillal. The following species are recorded from the Cardalitos shales. Of the twenty specifically determinable forms, twelve are re- stricted to this formation in northern Peru as far as known. Cancellaria sp. Conus (Dendroconus) bravoi Spieker, L. Z., Card., Sechura Acanthiza (Chorus) solida Nelson. U, Z. Northia guttifera Grzybowski. U. Z. Ficus ef. peruviana Spieker. LL. Z. Polwnices sp. Simum sp. Architectonica (Architectonica) sexlinearis Nelson. Tumbez Turritella abrupta Spieker. U. Z. *Turritella filicincta Grzybowski *Turritella altilira Conrad var. Turritella ef. infracarinata Grzybowski Nassa - Huthria - like gasteropod *Ostrea latiareata Grzybowski Arca (Cunearea) sp. “Arca (Diluvarea) dariensis Conrad *Arca (Diluvarca) colomba Olsson *Kucrassatella nelsoni Grzaybowski Nuculana (Saccella) acutisinuata Grzybowski *Lucina (Here) prosoptera Grzybowski *Pseudomiltha (Zorrita) petersoni Olsson *Pitaria (Pitarella) tumbeziana Olsson *Chione (Chamelia) grzybowski Olsson *Chione (Lirophora) grawensis Olsson *Dosinia lenticula Grzybowski Tellina sp. Panopea ef. coquimbensis d’Orbigny The following additional species were recorded by Grzybowski from the Upper Cardalitos shales at Mal Paso and Quebrada Hortensia. Leda acutisinuata is based on an internal cast. Venus munsteri D’Orbigny is possibly Chione grzybowski; Cytherea affinis has not been figured and its description is too meager for identification; Ostrea sculpta has the hinge of an Anomuia although its muscle scar seems to be that of an Ostrea; Cardiwm subaucanum is unfigured but said to resemble D’Orbig- ny’s Cardium auca; Cardiwm tenuimargo closely resembles a Chione; Lutraria Hortensis is probably a species of Harvella; Lutraria vetula Philippi is a Chilian species unknown to me. THE TUMBEZ FORMATION The highest division of the Peruvian Miocene was named the Tumbez formation by Iddings and Olsson because of the great 30 BULLETIN 68 30 development of these rocks in the Tumbez region. They consist principally of coarse yellow sandstones and conglomerates often with interbedded shales, lignites and beds of volcanic ash. From Quebrada La Cruz near Mal Paso, eastward to Tumbez and south along the Tumbez valley more than half the distance to Rica Playa, the Tumbez sandstones are the principal surface rocks. They form high, rugged hills overgrown with small trees and often impregnable thickets of Unas de Gato (Mimosa sp.) A narrow block of downfaulted Tumbez sandstones forms the cliffs at the village of Zorritos and extend from the mouth of Quebrada Grillo to Punta Santa Rosa. This block lies in fault contact with the Upper Zorritos sandstones and the Variegated beds. Near the mouth of Quebrada Tucillal, the Tumbez sand- stones are very fossiliferous and this is probably the locality where Bradley and Larkin collected most of the species described by Nelson. The sandstones of Mal Paso also belong to the Tumbez sandstones overlying a small thickness of the Cardalitos shales. The Tumbez sandstones overlying the Cardalitos shales form the high hills of Cerro Bruno and Cerro Tucillal and other hills along the divide between the east branch of Quebrada Zapotal, Quebrada Heath and Quebrada Charan. To the east of Quebrada La Cruz, the Tumbez sandstones form most of the hills as far as the Tumbez valley. The Tumbez formation is generally unfossiliferous and aside from oyster fragments, marine mollusks have been found at only a few localities. The largest and at the same time one of the most interesting faunas known from the Peruvian Miocene was described in 1870 by Nelson. The locality of these fossils is found near the mouth of Quebrada Tucillal at Zorritos. The fossiliferous rocks are interbedded sandstones and conglomerates and extend from the cement tank above the machine shop on the east bank of the Quebrada to a point a short distance above the Zorritos school on the west. The fossils occur in two zones sep- arated by approximately fifty feet of barren beds. The upper zone consists of hard, limy sandstones, sandy marls and comglomerates and has the greatest development. It contains several small species along with C/ione variabilis, angelana, 31 OLSSON: PrRUVIAN MIOCENE 31 Dosima grandis, Polinices subangulata, Buccinanops ( Perunassa) sorritensis, etc. The second zone consists of hard, blue shales along with some sandstones and conglomerates. The most im- portant species in this horizon are Turritella broderipiana altu- rana, Harvella elegans tucilla, Clementia dariena Conrad and Pecten nelsoni. A few fossils may also be found in the Tumbez sandstones between Mal Paso and Charan but consist mostly of casts of Cyrena and large mactroids. Several specimens of Arca (Senil- ia) garitensis were obtained from the sandstones along the ridge of La Garita. An echinoid collected by Baldry near Corrales has been described by Brighton” as Encope peruviana. Fifty-eight species of mollusks equally divided between the gastropoda and the pelcvpoda are recorded in the following list. Bullaria sp. *Cancellaria (Cancellaria) bradleyi Nelson *Cancellaria (Euclia) triangularis Nelson *Cancellaria (Huclia) larkinii Nelson *Cancellaria (Pyruclia) spatiosa Nelson *Cancellaria (————_)_ schuchk:erti Olsson *Cancellaria (Narona) trema Olsson Cancellaria (Aphera) peruana Nelson. L. Z. *Terebra (Strioterebrum) tafalla Olsson *Terebra (Strioterebrum) nelsoni Hanna and Israelsky *Conus (Dendoconus) cacuminatus Spieker *Conus (Leptoconus) bocapanensis Spieker Bursa (Crossata) ventricosa Broderip. Recent *Marginella incrassata Nelson *Solenosteira (Fusinosteira) alternata Spieker *Buccinanops (Perunassa) zorritensis Nelson *Murex laqueoratus Spieker Dolium sp. Strombina (Strombina) lanceolata zorritosensis Olsson *Polinices (Polinices) nelsoni Olsson *Polinices (Polinioes) subangulata Nelson Architectonica (Architectonica) sexlinearis Nelson U. Z., Card, Polinices (Polinices) ef. uber Valenciennes recent Turritella broderipiana alturana Spieker Turritella goniostoma Valenciennes recent Turbo (Callopoma) belli Spieker ?recent *Calliostoma (Eutrochus) noduliferum Nelson *Mitra dunbari Olsson *Surcula nelsoni Olsson Crucibulum (Dispotaea) inerme Nelson U. Z. Nuculana (Saccella) peruviana Dall U. Z.: *Arca (Cunearca) zorritensis Spieker 22Brighton 1927, Geol. Mag., vol. 638, p. 61. bo BULLETIN 68 32 (J) Arca (Noetia) reversa *Arca (Senilia) larkinii Nelson *Arca (Senilia) garitensis Olsson *Pecten (Plagioctenium) woodringi Spieker *Pecten (Plagioctenium) nelsoni Olsson *Pecten (Lyropecten) hopkinsi Olsson Anomia sp. Eucrassatella gibbosa tucilla Olsson *Cardium (Trachycardium) peruvianum Spieker *Cardium (Trigoniocardia) spiekeri Hanna and Israelsky *Dosinia (Dosinidia) grandis Nelson Clementia dariena Conrad L. Z., U. Z. *Pitaria (Hysteroncha) humboldtiana Olsson *Chione (Chionopsis) variabilis Nelson *Chione (Chionopsis) angelana Spieker Tellina (Eurytellina) ef. felia Hanley recent Tellina (Eurytellina) sp. Labiosa (Raeta) undulata Gould recent Tagelus gibbus Spengler recent Harvella elegans tucilla Olsson *Mulinia zorritensis Nelson *Corbula (—————) bradleyi Nelson *Corbula (Caryocorbula) nelsoni Olsson Corbula (Caryocorbula) ovulata Sowerby recent Corbula (Tenuicorbula) tenuis lupina Olsson Semele ef. flavescens Gould. Recent Panopea ef. coquimbensis d’Orbigny Card. Many indeterminate forms could be included such as Crepidula, Oliva, Ostrea, Spisula, etc., but since the affinities of these forms are not known, their inclusion would only serve to conceal the true relationship of the Tumbez fauna. Thirty-four species are restricted to the Tumbez formation or approximately 57.6%. There are sixteen recent species or sub- species of recent forms in the Tumbez fauna or approximately 27%. Only six species are known from the older Peruvian Miocene or about 10%. Although these figures are subject to considerable change as the Peruvian Miocene becomes better known, the distinctiveness of the Tumbez fauna from the older Zorritos faunas is clearly indicated. In the restricted sense, only nine species or 15.2% are recent forms or close to the original figure of 17% given by Lyell as characterizing the Miocene. ‘t is but fair that the ten forms which are subspecies of recent species should also be included as these shells would not have been separated in Lyell’s time. Their addition gives 27%, a figure midway between Lyell’s estimate of 17% for the Miocene w Co 33 OLSSONS PERUVIAN MrocENE and 35% for the Pliocene. This percentage or ratio supports the reference of the Tumbez formation to the Upper Miocene, a correlation already indicated by the stratigraphy and the dias- trophic history of the Miocene deposits of northern Peru. 2. SrcHuRA DISTRICT Outcrops of Miocene rocks in the Sechura desert are confined to a relatively narrow zone along the west side of the Illescas mountains and extend from Tric Trac Point near Bayovar, south for about eight miles. In places they are covered with Pleistocene and alluvial fan deposits so that their actual surface exposures are divided into two areas. The first exposures form the cliffs along the south shore of the Bay of Sechura and extend east fomubric Mkraczomtrog about three ailes, At Uric Prac Point, the Miocene strata lie in fault contact with the Bayovar shales of Lower Oligocene age. The second area of exposures is much larger and centers about Quebrada Montera. The thick- ness of the Miocene strata exposed in both places amounts to about 750 feet. _In Werenfels’ paper on the Illeacas region, these Miocene deposits are referred to the Eocene seemingly on valid paleontological grounds but it is certain that the Eocene species recorded by Werenfels are incorrectly determined Mio- cene fossils or else came from the Negritos or Paita region and not from Sechura. The Sechura Miocene or the Montera formation is composed of low-dipping and slightly faulted yellow sandstones. They are sometimes well-bedded at other times massive in character. The beds usually become more calcareous above and the outcrop of these upper layers form a hard arenaceous limestone. Fossils are abundant in the coast sandstones and along Quebrada Mon- tera but in many cases due to the hardness of the rock are diffi- cult to extract in perfect condition. *Glycymeris sp. *Barbatia (Cucullaria) sp. Arca (Diluvarca) sechurana Olsson U. Z. Arca (Senilia) ef. chiriquiensis Gabb Anomia berryi Spieker, Variegated *Ostrea sp. A. large saddle-shaped species *“Ostrea sp. B. Ostrea haitensis Sowerby 34 BULLETIN 68 at Pecten ef. gatunensis Toula *Pecten (Pecten) illesca Olsson *Lucina trietracensis Olsson *Lucina (Here) iduna Olsson *Miltha pacifica Olsson *Loripinus (Pegophysema) sechurana Olsson. U. Z. Eucrassatella aviaguensis peruviana Olsson Clementia dariena Conrad *Dosinia illesca Olsson Chione (Chionopsis) spiekert Olsson. U. Z. Macrocallista sp. Terebra sp. 2 Conus (Dendroconus) bravoi Spieker. Li. Z., U. Z, Conus (Leptoconus) multiliratus spiekeri Olsson. L. Z. Cancellaria (Cancellaria) ef. rowelli Dall Cancellaria (Cancellaria) ef. gabbiana Pilsbry and Johnson Turris (Pleurolira) sp. Oliva sp. Phos (Antillophos) ef. elegans Guppy ‘*Phos’’ phosoides Hanna and Israelsky. Zorritos Ficus sp. , *Solenosteiria sechurana Olsson Cerithium sp. Turritella larensis bayovarensis Olsson *Turritella illesca Olsson Turritella infracarinata Grzybowski. U. Z. Sinum sp. Polinices (Polinices) coronis Hanna and Israelsky. Variegated *“Hpitonvum sp. About thirty-seven species of mollusks have been collected in the Sechura Miocene but a few of these forms are too poorly preserved to be identified specifically at this time. About nine species belong to the Zorritos fauna such as Anomuia berry, Arca sechurana, Chione spiekert, Phos phosoides and Turntella infra- carinata. Eight species range northward into Ecuador or be- yond into the Caribbean province. They include Clementia dar- iena, Eucrassatella aviaguensis peruviana, Anonua berryi, Os- trea haitensis, Chione spiekeri, Pecten gatunensis and Turritella larensis bayovarensis. About thirteen species are known only from the Sechura Miocene. Such species are Dosinia illesca, Pecten illesca, Here iduna, Miltha pacifica, Loripinus sechura and Turritella illesca and give to this fauna a very distinctive aspect. The Montera formation is considered as Lower Miocene or Burdigalian in age and approximately the equivalent of the Upper Zorritos sandstones. 35 Ousson: PERUVIAN MIOCENE 35 The Miocene sandstones of Quebrada Montera and Tric Trac Point dip at a low angle eastward and disappear beneath the younger deposits which form the general surface of the Sechura desert. Beneath the tablazo escarpment at Yapate Point and around the margins of the great salt basin (see Werenfel’s map) there are extensive deposits of diatomaceous earth. Werenfels has reported the diatom Coscinodiscus oculus widis Ehrenberg while Willard Berry?* has described two species of Radiolaria from these beds or the overlying tablazo. These deposits of diatomaceous earth are clearly younger than the Montera sand- stones and probably lie directly above them. Their Middle Mio- cene age seems very probable. The Pisco formation of Adams?‘ exposed from Canete south across the Paracas Peninsula was considered by Adams as Plio- cene or Quaternary in age. They often contain important de- posits of diatomaceous earth and Adams has also reported zones of fossil mollusks and whale bones. The Pisco formation is transgressive over Mesozoic or older rocks while in other locali- ties the underlying beds have been considered as Eocene. Al- though paleontological evidence is at present lacking, it seems probable that the diatomaceous earth deposits of Sechura and the Pisco region are approximately of the same age and that they were deposited in the same sedimentary basin or province. In the present oceans, diatomaceous ooze is principally being formed in the cooler regions of the earth as for example in the north Pacific off the coast of the Aleutian and Kamchatka penin- sulas and a much larger belt extending completely around the earth exists in the sub-Antarctic regions. The most important deposits of marine diatomaceous earth, mainly of Middle Miocene age were laid down in cool or temperate waters. Such are the deposits found in the Chesapeake Miocene of Maryland and Virginia and those of the coast ranges of California. Deposits of diatomaceous earth are also known in New Zealand in rocks of probable Miocene age. 23Willard Berry, 1929, Journ. Washington Academy of Science, vol. 19. no. 7, pp. 145-148, 4 figs. 24Adams 1908, An outline review of the Geology of Peru, Smithsonian Report for 1908. 36 BULLETIN 68 36 A few Caribbean species such as Clementia dariena, Ostrea haitensis, and Eucrassatella aviaguensis peruviana are found in the Sechura Miocene but the extensive development of diatoma- ceous earth is proof that the Miocene seas of Sechura and Pisco were distinctly cooler or less tropical in character than that in which the Zorritos rocks were deposited. The Negritos region was therefore in Miocene times as it is today, the dividing line between two faunal provinces, a warm, tropical, Panamic-Antil- lean province on the north and a cooler Peruvian-Chilian pro- vince on the south. It is therefore not surprising that the Zor- ritos fauna and that of Chile shou!d not have a great deal in common. As our knowledge of the Sechura Miocene increases a closer relationship of the Sechura fauna with the Chilian can be expected. III CorRELATION AND AGE Correlation of the American Tertiaries with those of Europe stage by stage cannot yet be attempted on a strictly paleontologi- cal basis. On the other hand, the Middle Oligocene or Stampian- Rupelian age of the Antiguan formation of the Leeward islands and the Middle Miocene or Helvetian age of the typical Gatun- Gurabo fauna is conceded by most American paleontologists and these key faunas have been the basis of most trans-Atlantic cor- relation of the post-Eocene formations in tropical America. The constant and fairly regular alternation of marine shale with shallow-water sandstones and conglomerates in the Peru- vian Tertiary formations illustrate in a remarkable and detailed manner a series of cycles of deposition or a constant shifting or migration of the strand-line according as these rocks were formed during a transgressive or regressive sea. Similar cycles of deposition are clearly revealed in the Tertiary sections of Colombia and Central America and when properly regarded in connection with paleontological evidence their use in classifica- tion and the correlation of the rocks concerned is very important. The following diagram is intended to show graphically the major oscillations of sea-level during the Middle and Upper Oligocene and Miocene epochs in northern Peru. Two major transgres- 37 OLSSON: PERUVIAN Mi0ocENE 37 north south Pliocene emergence sandstones conglomerates Cardalitos formation Zorritos transgression shales Miocene sandstones U. Zorritos partial emergence Variegated lignites L. Zorritos sandstones Heath formation shales Heath transgression Oligocene Mancora sandstones formation} conglomerates Fig. 1, Diagram illustrating the migration of the strandline in northern Peru during the Upper Oligocene and Miocene epochs. sions are indicated. The older or the Heath-Mancora transgres- sion has already been described in an earlier Bulletin of this se- ries. This transgression culminated in the deposition of the 38 BULLETIN 68 38 Heath shales or their equivalent rocks over a large area, indi- cating complete flooding of the Bolivar geosyncline through northern and western South America. This late Oligocene trans- gression nearly equalled the marine invasions of the Upper Eo- cene and represents a very important period of Tertiary deposi- tion in northern South America. The close of this cycle wit- nessed renewed emergence and a general retreat of marine wa- ters to the deeper portions of the Bolivar geosyncline. In the shallowing waters a purely shale type of deposition was there- fore replaced by one of sands and conglomerates and this condi- tion was true not only in Peru but in Ecuador and northern Colombia as well. As a result of an eastward shift of the Boli- var trough at the close of the Upper Oligocene, the Lower Zor- ritos was transgressive for a short time, in the Tumbez region but in general the early Lower Miocene was a time of emergence and shallowing seas in northern South America. The Lower Zorritos sandstones are therefore principally regressive deposits. The general retreat of the Heath sea northward into the Daule basin of western Ecuador was synchronous with a corresponding recession of marine waters southward in the Sechura district and the rise of a land-barrier which in Miocene times divided the Zorritos district from that of Sechura. The Zorritos district was probably never completely above sea-level at this time and there were locally formed the peculiar deposits which Spieker has called the Variegated beds. Although a few marine layers occur in the Variegated beds the fossils are often worn and many belong to brackish-water types while the lignites, conglom- erates and brilliant colored shales indicate a deltaic to subaerial mode of origin. - The Lower Miocene emergence was followed by subsidence and the commencement of a Miocene transgression which reached its greatest expansion in Gatun or Helvetian times. This transgression was very extensive through the Antillean and Car- ibbean region or in the Tethyian geosynclines in general but along the West Coast of South America, its area of influence was small and the land barrier in the Chira-Negritos region was not again submerged. In Peru, this transgression commenced \vith the deposition of the Upper Zorritos sandstones followed by 39 OLSSON: PERUVIAN M10CENE 39 the formation of the Cardalitos shales. The upper Cardalitos shales are regressive deposits passing rapidly into the Tumbez sandstones and conglomerates partly marine and partly subaerial in origin. The early Pliocene again saw complete withdrawal of marine waters from the Tertiary region of northern Peru, un- less such deposits occur in the Sechura desert, and the final clos- ing of oceanic connection between the Pacific and the Atlantic. The late Oligocene age of the Heath shales has been discussed in an earlier paper of this series and need not be further consid- ered here. On the other hand, the Miocene age of the Lower Zorritos formation cannot be questioned. In some sections such as Zapotal there is no break betweeen the typical Lower Zorritos sandstones and the Heath shales and consequently a lower Lower Miocene or Aquitanian age of the Lower Zorritos formation must be taken for granted. An interesting fauna of Lower Miocene age was described by Anderson”* in 1929 from the shales exposed at Puerto Colombia in northern Colombia. These beds were called the Las Perdices group and were considered as Aquitanian in age and equivalent to the Uscari shales of northern Costa Rica. The typical Las Perdices shales are the upper part of a thick, predominantly shaley series which passes downward into coarse sandstones and conglomerates of Middle Oligocene age. This shale section is therefore the exact duplication of the Heath shales of Peru, the upper part, the Las Perdices shales being regressive deposits formed during the early or Aquitanian Miocene. The fossilifer- ous Las Perdices shales are limited to the coast section at Puerto Colombia and Puerto Caiman and as Anderson has shown contain an abundant fauna very similar to the Dentalium uscar- ianum - Ptychosalpinx ¢° zone of the Upper Uscari shales of northern Costa Rica and western Panama; they pass into sand- stones further south in Atlantico. Anderson was further able to prove that a stratigraphic break corresponding to the Gatun un- conformity of Panama and Costa Rica separated the Las Per- dices from the overlying Tubera group, the lower part which he referred to the Burdigalian. 25Anderson 1929, Proc. Calif. Acad. Sci., 4th series, vol. 18, p. 89. 40 BULLETIN 68 ; 40 The Tubera group was named by Anderson in the same paper. These deposits consist usually of soft sands and are well ex- posed in Tubera mountain in northern Colombia near Barran- quilla. The upper half or Zones P-S of Anderson contains a fauna distinctly Gatun in character and may be correlated with the Lower Gatun of the Canal Zone. Anderson’s correlation of the lower Tubera or zones M-O with the Burdigalian seems justifiable. Above the Tubera sandstones lies a series of shales centering near Juan de Acosta and the few fossils which have been found in these rocks are of Gatun age. The Juan de Acosta shales are succeeded by the sandstones and conglomerates of Usiacuri which Woodring?® has shown belong to the Upper Miocene. The importance of Anderson’s contribution to the strati- graphy of northern Colombia is the recognition that the Gatun transgression commenced in the Lower Miocene or Burdigalian. A close parallel in time between the Helvetian or Vindobonian transgression in the Alpine or Mediterranean regions of Europe and the Gatun transgression in America is thereby indicated. According to Haug?’, the seas in the folded regions of Europe were again recessive during the Tortonian becoming reduced to a chain of lakes over the northern or molasse region of Switzer- land in the Pontian or Sahelian. Grzybowski and Spieker considered the Zorritos Miocene as Burdigalian in age. Grzybowski came to this conclusion from a study of a rather small collection of fossils from the Upper Zorritos sandstones and the Cardalitos shales. Spieker how- ever included in his Zorritos fauna, fossils from the Lower Zor- ritos to the Tumbez or the whole of the Peruvian Miocene. In the restricted fauna from the Variegated beds and the Upper Zorritos formation there are no species which can be considered as typical Gatun forms. On the other hand, several species give this fauna a characteristically Lower Miocene aspect. The group of Arca chiriquiensis is abundant in the Lower Miocene rocks 26Woodring 1928, Miocene Mollusks from Bowden, Jamaica, Pt. 2, Gastro- pods and discussion of results. Carnegie Institute of Washington, No. 385, p. 79. 27Haug 1900, Les Geosynclinaus et les Aires Continentales, Bulletin de la Societe Geologique de France 3rd ser., tome 28, p. 707. 4] OLSSON: PERUVIAN MI0cENE 41 of Colombia and the West Indies. Cardiwm (Dinocardium) ecuadorialis occurs in the Upper Zorritos sandstones and in beds of the same age in Ecuador. A large Dinocardium is common in the Lower Miocene sandstones (Gatun(?) of Reeves and Ross?®) at Madden Dam, Alhajuela, Canal Zone. A species of Dinocardium also noted by Woodring’? is common in the Lower Miocene rocks in the Sinu valley of northern Colombia. Other species which give this fauna a Lower Miocene rather than a Middle Miocene appearance are Anomua berryi (also occurs in the Sechura Miocene and the Lower Miocene of Colombia). Labiosa (Raeta) undulata gardnere and Turritella abrupta (also a Middle Miocene species). The Cardalitos fauna is not well known as only the upper part of this shale formation is fossiliferous. Such species as Turri- tella altilira, Pitaria (Pitarella) tumbezana (near gatunensis ) Arca (Diluvarca) dariensis, Arca (Diluvarca) colomba and Eucrassatella nelsoni have a Gatun or Middle Miocene appear- ance. The Upper Miocene age of the Tumbez formation has been discussed earlier in this paper. It corroborates the evi- dence just reviewed as to the Middle Miocene or Gatun age of the Cardalitos formation. Correlation of the Peruvian Miocene deposits with the Carib- bean coast of Colombia and with northern Chile is given in the table on the following page. IV. Fauna AFFINITIES As the Caribbean Miocene deposits of northern Colombia, Central America and the Antillian region in general, contain a large Pacific element in their faunal makeup, it is not surprising that the Peruvian Miocene should display strong Caribbean affinities in its turn. This fact has already been noted by Grzybowski and Spieker who likewise found very little or only doubtful relations with the Tertiary faunas of Chile and Pata- gonia. The reasons for this faunal similarity between the Pa- 28Reeves and Ross 1930, Bull. 821-B, U. S. Geol. Survey, p. 14. 29Woodring 1928, op. cit., p. 79. BULLETIN 68 42 42 ueiduie3S uenyeyD uziueyinby “2OTLOULY WQnog ysamM pu [eIyUED Jo QUSDOIP, PUB OUBd0ST[Q oY} FO 9[qVJ, WOr}ee110/) Souo}SaUIT] ‘s[3u00 O1yog TeproyqiO eg Quoz nypzuag eiqa[nd 1aM0'7T B1q9[ND raddQ ‘s] soperadurq “ss oqures uoneuLioy 1H89S() UOT} eULIO} 4s avon | unyey) uenuog Gulouesield uensy dUu0]SOWIT joes | se00g wo un'T Vola VLSOO |ANOZ IVNVO a} 219UI0[ Sud souo}spues poe sareys sadIpled sey oe < & ry @ ° e ao) saeys s9uO}spues Lingeis() VIENOTOOD ‘sayeys pelng UOI}RULIOS e19}U0W yuiea SnoadeUlo}eIp UOT}BUTIO} eanyI2S Van HOaS 6 SL uo eULIOy eIOOULIAL UOIJLUIIOY wee SOPOT “J payesaue,, SO}IIOZ ‘(1 UOT} eULIOY so} epsed UOT}BULIOY saquiny, ozeiqr} eIOIUL I SOLIYAOZ dno13 s0}11107 spaq Peplraen speq oquiinbo-) 43 OLSSON: PERUVIAN MIOCENE 43 cific and Caribbean provinces is now well understood. Until near the close of the Miocene, two or more straits along geosyn- clinal troughs connected Pacific and Atlantic waters and it is through these straits that-faunal intermingling took place. The continuity of Tertiary deposits from northern Peru to northern Colombia through the Atrato and San Juan valleys or along the Bolivar geosyncline, is proof that a continuous shore-line at one time extended from Peru to northern Colombia. Many species and genera which are now characteristically Pacific since they are no longer living in Caribbean waters, may actually have had a Caribbean or more eastern origin. Certain genera as Xancus, Bursa, Miltha and Clementia which first ap- pear in the Eocene deposits of Peru are probably of Pacific origin, spreading eastward into the Antillean and Mediterranean geosynclines during the late Eocene and Oligocene. Xancus still living in the Caribbean and more eastern waters is unknown as a fossil on the Pacific coast above the Oligiocene. It is unnecessary to list or review all the species common to the Peruvian and Caribbean Miocene and only a few cases will be mentioned here. Lab.osa (Raeta) undulata Gould is a recent West Coast species first described from Lower California but quite common along sandy shores in northern Peru. As a Mio- cene fossil it is common in the Tubera formation and Mrs. Hodson*® has recently recorded and figured this species from Venezuela. In Peru, it is found in the Tumbez formation. Chione propinqua Spieker is very near Chione paraguanensis H. K. Hodson*! from Venezuela. Anomia berryi Spieker ori- ginally described from Zorritos occurs in the Lower Miocene deposits of northern Colombia. Dosinia grandis Nelson is known from the Miocene of Trinidad as Dosinia titan Maury**. Arca (Noetia) retractata Hanna and Israelsky is hardly distinguish- able from Arca macdonaldi Dall** from Costa Rica and Colom- bia. Melongena melongena consors Sowerby first described from 30H. K. Hodson 1931, Bulls. Am. Pal., vol. 16, p. 21. 31H. K. Hodson 1927, Bulls. Am. Pal., vol. 18, p. 62, pl. 35, figs. 2, 7. 32Maury 1925, Bulls. Am. Pal., vol. 10, p. 139, pl. 24, figs. 1, 2, pl. 25, fig. 3. 33Dall 1912, Smith. Mise. Coll., vol. 59, No. 2, p. 9; also Dall 1925, Proc. U. S. Nat. Mus., vol. 66, p. 5, pl. 17, fig. 9; also Olsson 1922, Bulls. Am, Pal., vol. 9, p. 366, pl. 25, figs. 4-7. 44 BULLETIN 68 44 Santo Domingo but common throughout the Caribbean region, in Lower Miocene times extended its range south into northern Peru. Its living form Melongena melongena is still living in the Caribbean province. Melongena colombiana Weishord** de- scribed from northern Colombia is quite common in the Varie- gated beds- along the Tumbez river. Of the Miocene species recorded from northern Peru about 17% occur in Caribbean deposits or have closely related forms in those beds. This per- centage or ratio would be greatly increased through the descrip- tion of the Miocene faunas of northern Colombia as these de- posits situated along the Bolivar geosyncline contain a much _larger Pacific element than is true of the Miocene deposits else- where in the Caribbean and Antillean region. The relationship of the Peruvian Miocene to deposits of the same age in Chile and Patagonia is very slight. Although the Chilian Tertiaries were deposited in warmer waters than those which now wash its shores, they were distinctly cooler than those of the Zorritos Miocene and consequently belonged to another faunal province. The faunal difference between the Chesapeake Miocene of the Atlantic states and the tropical Antillean Miocene is due to a similar cause and of no greater significance. The Navidad beds of central Chile which have been. considered as Lower Miocene by some authors are probably Upper Oligocene while the Coquimbo beds as previously noticed are late Pliocene in age. Close faunal similarities between these horizons and the Zorritos Miocene cannot therefore be expected. Several Zorritos species were identified by Grzybowski with Chilian forms but in no case have these determinations been verified. A species described by Grzybowski as Struthiolaria guttifera has proved to be a nassoid allied to Northia and there- fore a Panamic and not a south Pacific type. Arca valdiviana - Philippi, Lutraria vetula Philippi, Psammobia darwini Philippi and Venus munstert D’Orbigny are Chilian species recorded by Grzybowski from Zorritos, Caleta Grau and Rica Playa but they are probably not correctly determined. | Distorsio ringens Philippi*® described from Navidad and Ma- 34Weisbord 1929, Bulls. Am. Pal., vol. 14, p. 275, pl. 7, figs. 2-4. 35Philippi 1887, Die Tert. und Quart. Versteinerungen Chiles, p. 56, pl. 4, fig. 9. 45 OLSSON: PERUVIAN MI0CENE 45 tanzas Chile may occur in the Lower Zorritos deposits of Zapotal. If the Zapotal shell is correctly determined, ringens is a subspe- species of decussatus Valenciennes, a living West Coast species or a tropical form which spread southward into Chile during the Oligocene. Many of the Zorritos species which are unknown in the Caribbean deposits are probably of southern origin. To this class belong Acanthiza sula cruziana Olsson, Acanthiza (Triumphis of Spieker) solida Nelson, and Buccinanops (Peru- nassa) zoritensis Nelson. Panopea cf. coquimbensis from the Cardalitos and Tumbez formation may be the same as D’Orbig- ny’s species from Coquimbo but only the internal cast of the typi- cal species has been figured so that determination is not certain. V. TERTIARY History oF THE WeEsT Coast oF SouTH AMERICA INTRODUCTORY REMARKS The Tertiary deposits of northern Peru extend from southern Ecuador south to Chiclayo and Lambayeque. In the southern region commonly known as the Sechura desert, the Tertiary for- mations are usually concealed beneath Pleistocene or more recent deposits, or out-crop in narrow fault blocks around the foot of the Cerros de Illescas. North of the Chira valley, the Tertiary rocks are exposed over a large region and from Mancora to Tumbez, they form practically the entire surface of the coastal region. On the north side of the Gulf of Guayaquil, the same belt of Tertiary formations extend across western Ecuador lying between the Andes and the coast. They continue northward as a narrow band along the coast of Colombia, passing across the low San Juan divide into the Atrato valley to the Caribbean slope. The major part of the Tertiary region of northern Peru has been elevated to its present height above sea-level by an uplift, geologically recent in age. The extent and character of this re- gional uplift is well shown by the distribution of the curious marine terraces or Pleistocene sea-bottoms commonly known as tablazos. These tablazo plains are usually not level but from Se- chura rise northward, reaching their highest elevation above sea-level at Cabo Blanco. In the southern part of the Sechura desert, the low, undissected tablazos have the appearance of coastal plains recently abandoned by the sea. At Paita, the Man- cora tablazo has risen to a height of about 200 feet. At La 46 BULLETIN 68 46 Brea, the same tablazo lies at 400 feet while at Cabo Blanco, directly on the coast, this tablazo has an approximate elevation of t1oo feet but decreasing both inland and along the coast. Similar local uplifts have affected the coast region of western Ecuador and may be seen in the rise and fall of the tablazo levels along the shore. Bosworth*® who carefully described the Peru- vian tablazos, apparently did not appreciate the significance of the gradual rise or tilting of the tablazo levels from Paita north to Cabo Blanco and their importance in the recent tectonic de- velopment of northern Peru and western Ecuador. Lisson** was the first to show that extensive submergence has occurred along stretches of the Peruvian coast and the data bear- ing on this problem have been summarized by Steinmann**. This submergence was not uniform but greatest in the zone extend- ing from Illescas (Chiclayo) to Paracas and along a second zone extending from Caraveli to Arica. It is principally in the first zone (No. 3 of Steinmann) or from Chiclayo to Paracas that evidence of great subsidence is most conclusive in the form of submarine river channels, out-lying islands, absence of Tertiary formations while Cordilleran rocks such as Mesozoic sediments and Tertiary granites line the coast. The Lima deep which reaches a depth of nearly 6,000 meters occurs in this stretch. South of Canete and Paracas, Tertiary deposits appear again in the coast sections and extend nearly to Caraveli. The coast be- tween Caraveli and Arica again shows signs of submergence cul- minating in the Arica deep of over 6,000 meters. North of Ecuador, the Gulf of Panama is of recent origin. As shown by Hershey*®, the coast of southern Panama is that of a land whose borders have recently subsided and been partially submerged. This recent submergence is clearly seen in the drowned river mouths such as the Rio Tuyra and Montijo in which tide water ascends 30 to 40 miles from the open ocean. Hershey noted particularly that this depression has been great- 36Bosworth 1922, Geology of the Tertiary and Quaternary periods in the North-West part of Peru, Part 111 pp. 148-260. 37Lisson 1900, Boletin de Minas, Tomo 16. 38Steinmann 1929, Geologie von Pert, Heidelberg, pp. 295-296. 39Hershey 1901, The Geology of the Central Portion of the Isthmus of Panama, Univ. of Calif., Bull. Dept. Geology, vol. 2, No. 8, pp. 262, 264. 47 OLSSON: PERUVIAN MIOCENE 47 est on the ends of long headlands and relatively slight at the heads of deep bays pointing to a slight tilting of the interior towards the south or towards the sea. In the interior of Panama, Hershey found strong evidence of uplift indicating an arching of the interior of Panama, probably contemporaneous with the progressive submergence of the coast lands towards the south. The evidence is therefore fairly conclusive that the rise of the coast in northern Peru (the Amotape Gebiet of Steinmann) and western Ecuador was compensated by corresponding sinking of the region to the south (Chiclayo—Paracas) and to the north (Bay of Panama). The peculiar bulge of the west coast of South America between Chiclayo and Tumbez and the still greater one in western Ecuador give a rough outline of the extent of this regional uplift. The Gulf of Guayaquil appears to be a downwarped zone between these two major areas of uplift. A detailed study of the Tertiary sedimentary deposits of northern Peru and their areal distribution has clearly shown that the marine incursions or transgressions came generally from the south or southwest, progressively overflowing a littoral re- gion situated to the northeast while in Miocene times, the areas receiving deposition were divided by the uplift of a land barrier in the Cabo Blanco-Negritos-Paita region. In Ecuador, the Ter- tiary section is probably not as complete as that of northern Peru and the earlier Tertiary formations in particular have been. greatly affected by intrusions of igneous dikes and the formation of large chert bodies. These observations seem to indicate that in Tertiary times as well, there has been a constant tendency for the uplift and formation of a North Peruvian-South Ecuadorian arch similar but smaller than the coastal bulge described above. It is probably through the operation of these forces of doming or upthrusting that the intense deformation of the Peruvian Tertiary deposits, mostly by way of normal or gravity faulting, has come about. The occurrence of land in the eastern Pacific since early Paleozoic to near the close of the Tertiary has been repeatedly advanced by many geologists such as Steinmann, Burkhardt*® 40Burekhardt 1900, Traces Géologiques d’un Ancien Continent Pacifique Revista del Museo de la Plata, Tome 10, page 177 et suivantes. 48 BULLETIN 68 48 and Berry*!, and Von Ihering came to the same conclusion from his zoogeographical studies. Haug‘? pustulated land in the east- ern Pacific as a fundamental basis of his theory of the forma- tion of the Andean geosyncline. Steinmann** has referred to these old lands lying off the Peruvian coast as Macizo Pacifico (Pacific Massive) ; and Von Ihering”, as Burkhardtland. These views have been substantiated in this study at least for Tertiary times and have further indicated that central Panama and the coast ranges of Western Colombia and Ecuador were a part of this old land mass during the Cretaceous and Tertiary epochs. How far westward these lands may have extended into the Pa- cific is entirely conjectural but it seems very doubtful that they were ever large enough to form a truly Pacific continent as be- lieved by Haug and lately accepted by Gregory** or that the major contours of the Pacific basin were ever greatly modified. Pres- ent evidence rather indicates that the Pacific lands were rela- tively narrow, as they have been destroyed by the western mi- gration of the coast of South America. The western migration of the Pacific coast at the continued ex- pense of the Pacific forelands is shown. This fact is evident from early Paleozoic times since Paleozoic formations find their greatest development in the eastern Andes and as Berry has noted, become progressively less marine westward towards the present coast. That the eastern Andes are older than the west- ern chains seems probable from these considerations. The Andean geosyncline in which the Cretaceous beds were deposited lies west of the earlier Pennsylvanian trough and in turn is fol- lowed by the Tertiary or Bolivar geosyncline and the present shores. 41Berry 1922, Outlines of South American Geology, Pan-American Geolo- gist vol. 38, pp. 191, 216, several other papers. 42Haug 1900, Les Geosynclinaux et les Aires Continentales, Bulletin de la Societe Geologique de France, 3rd ser., tome 28, p. 662. 43Steinmann 1929, Geologie von Peru, pp. 314, 315; see also Lisson 1925, Como Se Genero El Suelo Peruano. Bol. de la Soc. Geol. del Peru, Tome 1, pp. 97-126. 44Von Ihering 1931, Land-bridges across the Atlantic and Pacific Oceans during the Kainozoic Era, Quart. Journ. Geol. Society, vol. 87, pt. 3, 376-391. 45Gregory 1930, The Geological History of the Pacific Ocean. Anniversary Address of the President. Quart. Journ. Geol. Soc. vol. 86, pt. 2, pp. LXXII- 4.9 OLSSON: PERUVIAN MrocENE 49 The broadening or western swing of the Andean geosyncline in northern Peru during the Cretaceous period together with the occurrence of marine Pennsylvanian in the Amotape region, seems to indicate a branch or equatorial geosyncline extending westward into the Pacific. During the Pennsylvanian, this geo- syncline was probably a part of the equatorial trough extending eastward through the Amazon valley and in which the Brazilian Pennsylvanian deposits were formed.. Further evidence on this problem are the WNW _=§ strike and fault’ trends de- scribed by Stappenbeck*® and others from the Chicama ‘region. This peculiar structure, entirely at variance with the normal N-S Andean trend is evident as far north as the Negritos region. The important Pananga fault cutting through the Amotape mountains separating Pennsylvania slates and granites from down-faulted Cretaceous shales on the north trends approximately N. 58° W. with a throw measured in thou- sands of feet. This fault does not affect the Tertiary deposits to any great extent and its origin was probably contemporaneous with the general folding and uplift of the Andean region at the close of the Cretaceous. Steinmann*’ has interpreted the Chi- cama structure as part of an old mountain system which he names the Chimu Andes (Chimuandes projecting north- westward into the Pacific as far as the Galapagos. The geology of the coast mountains which includes the Amotapes, the Cerros de Paita, the Cerros de Il'escas and the Lobos Islands does not support Steinmann’s views. In these slate, schist and granite mountains, the strike of the bedded rocks and ridges does not parallel the Chicama structure but lies at almost right angles to it. On the other hand, the origin of the Chicama structure is greatly simplified if it can be shown to be purely a series of frac- tures or faults in a shear-zone developed in the corner between two geosynclinal troughs. The disappearance of the Pacific forelands south of Punta Aguja (the Macizo Parifico of Steinmann) in the late Miocene 46Stappenbeck 1924, Das Chicamatal in Nordperu, Zeitschr. Ges. Erdk. 1-12; Steinmann, Geologie von Peru, pp. 313-314. <7Steinmann 1929, op. cit., p. 314. BULLETIN 68 50 Fig. 3. Approximate position of the Bolivar geosyncline and its Pa- cific forelands OU oo BO . The Bolivar geosyncline . The Costa Rican geosyncline The Pacific outlet Early Panama lands . The Pacific Massive of Steinmann Stippled areas indicate marine Miocene Eeuador deposits in Peru and 51 OLSSON: PERUVIAN MIOCENE Fal and Pliocene, permitted the north branch of the Antarctic drift or Humboldt Current to flow north along the coast of Peru and Chile with its resulting influence on the climate of the region. The continued sinking of the Peruvian coast south of Illescas as shown by Lisson’s studies with its compensating rise of northern Peru and western Ecuador, and accompanying severe seismic disturbance in historical times still show the tectonic instability of this region and that complete isostatic adjustment has not yet been attained. THE BOLIVAR GEOSYNCLINE During the Cretaceous period, the formation of marine de- posits was taking place through the Andean geosyncline from eastern Venezuela through Colombia, Ecuador, Peru to Chile and Argentine and the waters of the Pacific region communi- cated freely with those of the Atlantic. In Colombia and Ecua- dor, this strait was bordered on the north by land which stretched from the Goajira peninsula of Colombia westward to Panama and south to western Ecuador. No Cretaceous rocks have been identified on paleontological grounds in the Sinu or Atrato re- gion of northern Colombia or is it likely that they underlie the Tertiary formations of that region. No Cretaceous rocks are definitely known in Panama and Costa Rica although some of the older Panama formations have frequently been classed as Cretaceous but without paleontological proof. Wolf#® on. his geological map of Ecuador shows a considerable development of Cretaceous in southwestern Ecuador in the Province of Guayas. This conclusion is based principally on his discovery of Inoceramus at Guayaquil. Recently Sheppard*® has questioned the occurrence of Cretaceous beds at Guayaquil through his discovery of foraminiferal sections in the siliceous limestones of Guayaquil which Vaughan has determined as Discocyeclina. It seems extremely doubtful that the Siliceous limestones of Guayaquil and the Sierras de Chongon are entirely Eocene 1a age as they have no counterpart in the Eocene sections of north- ern Peru. In 1924, Dr. J. S. Stewart and I were able to establish ® 4SWolf 1892, Geografiay Geologia del Ecuador, Pl. 1 and p. 243. 49Sheppard 1929, The Age of the Guayaquil Limestone, Bull. Amer. Assoc. Petroleum Geologists, vol. 138, pp. 383-384. BULLETIN 68 52 On bo the Middle Eocene age of the thick, coarse conglomerates of the Cerros de Chanduy through the discovery of a small fauna of Parinas and Clavilithes affinities in those beds. On breaking a boulder of arenaceous limestone from the Chanduy conglom- erates, a large specimen of Inoceramus was found. It is clear that this limestone boulder could not have come from a great dis- tance and it proves the presence of Cretaceous in western Ecua- dor although these beds may now be covered by younger strata or possibly destroyed. Although Wolf did not actually find Cretaceous fossils in place but reported them from slabs in the streets of Guayaquil and in buildings and walls, his record of Inoceramus or of Cretaceous beds at or near Guayaquil cannot be lightly dismissed. The Chanduy sandstones and conglomerates previously referred to, are shore deposits and overlie an older more strongly metamorphosed series of slaty-like beds whose age has not been established except that in all probability they are pre-Tertiary. Near Azucar, Stewart and I collected in these beds a fossil resembling a small Discina-like brachiopod while south of Guayaquil at Punta Piedra, there are slaty-like rocks which closely resemble the Amotape slates in appearance. Whether or no, the Guayaquil limestones are Eocene or partly Cretaceous in age, is not very important, but it is certain that Cretaceous and pre-Cretaceous rocks occur in southwestern Ecuador. Cretaceous formations are known to underlie the Tertiary deposits of northern Peru and their outcrop is extensive. Large blocks of Pananga limestones occur in the Upper Eocene of Quebrada Culebra near Caleto Mero. Extensive outcrops of Cre- taceous black shales and limestones are found in upper Quebrada Parinas (Muerto), Quebrada Pazuil and in the Chira valley. Gerth®® has reported the discovery of late Cretaceous Rudistids and other fossils on the south side of the Paita mountains. These Cretaceous formations are similar to the Cretaceous types of the Andes and show a western swing or a Pacific arm of the Andean geosyncline in northern Peru. At the close of the Cretaceous, folding and uplift was general 50Gerth 1928, Neue Faunen der oberen Kreide mit Hippuriten aus Nord- peru, Leidsche Geologische Mededeelingen, Deel 11, Aflevering 4, V 1928, pp. 231-241. 53 Ousson: PERUVIAN MIocENE 53 along the Andean geosyncline through its entire extent in the formation of the Andes. As a compensation to this uplift, down- folding to the west, resulted in the formation of a Tertiary geosyncline along its west border. In northern Colombia and Ecuador, this new strait seems to have encroached on a region which had been land during the Cretaceous or covered simply by marginal or non-geosynclinal waters. Communication be- tween the Pacific and Atlantic or Caribbean region was again restored accounting in part for the strong Pacific element in the Tertiary faunas of northern Colombia as well as the extension of Caribbean types along the West Coast. This new geosynclinal trough may be called the Bolivar geosyncline differing from the great Andean geosyncline in its later formation and location. Schuchert classifies the Andean and Cordilleran geosynclines as polygeosynclines, differing from the simple monogeosynclines of the Appalachian type, in giving rise to one or more geanticlines and two or more sequent geosynclines with shorter history. Con- sidered in this light, the Bolivar trough would be classed as the last sequent geosyncline of the Andean polygeosynclinal sys- tem, its activity ending with the foundering of the Pacific fore- lands near the close of the Miocene and early Pliocene. It is particularly in northern Colombia that the geosynclinal character of the Tertiary deposits of this sedimentary belt is best shown. Unlike the marginal deposits of the Panama Canal Zone, the Tertiaries of northern Colombia like those of Costa Rica, are usually very thick; they are generally moderately deep- water deposits and have been deformed through intense folding and faulting. The Tertiaries of Ecuador and northern Peru are very similar to those of Colombia but instead of folding they have suffered through excessive normal or gravity faulting. On Huntley and Mason’s*' geological map of northern Colom- bia, the Tertiary formations of the Caribbean coast are shown extending up the Atrato valley and across the low divide of the San Juan to the Pacific. The most complete account of the geology of the Atrato and Uraba region is given by Hubach* 51Huntley and Mason 1923, Colombian Oil Fields, Trans. Am. Inst. Min. and Metallurgical Engineers, vol. 58, p. 1015, fig. 1. 52Hubach, Enrique 1930, Informe geologico de Uraba, Boletin de Minaspauy Petroleo, Tomo IV, Numeros 19 y 20, pp. 26-136., Ministerio de In- dustrias, Bogota Colombia. 54 BuLLETIN 68 54 which although quite detailed in some respects, gives practically no paleontogical information and the correlation of the sedi- mentary formations is principally based on their physical char- acteristics or their relations to one another. Hubach has differ- entiated the following formations in Uraba and the Pacific region. Upper Tertiary: Piso del Cuchillo; Piso del Pacifico. Unconformity. Piso del Curralao with probable equivalents in the Pacific. With probable unconformity. Lower Tertiary: Piso de los Tacanales with probable equival- tents in the Pacific. Probable unconformity. Piso de Nuguiales. Has not been found in the Pacific. The age of these formations must of course remain unsettled until their faunas are made known but it is probable that Eocene, Oligocene, Miocene and possible early Pliocene deposits are represented in this section. The Pacific region of western Colombia is divided by Hubach into two physiographic and structural provinces. The first or the Cordillera de la Costa (Coast Range) or Sierra de Baudo is a discontinuous or broken range of low mountains composed of transitional and probably pre-Tertiary rocks, extending from Garachiné point in eastern Panama, along the Pacific coast of Colombia through Cabo Corrientes, Isla de Gorgona then skirt- ing the Colombian coast until it joins with the coast mountains of western Ecuador near Esmeraldas. Between the Coast Range and the western slopes of the Cordillera Occidental there is a broad trough which Hubach has named the Depression del Pacif- ico (Pacific Depression). It extends through the Atrato and San Juan valleys to Buenaventura and southward through the littoral region of western Colombia into Ecuador. Troll®* has recently described the continuation of the physio- °8Troll, Carl., 1930, Die geologische Verkettung Siid= und Mittelamerikas. Mitteilungen der Geographischen Gesellschaft in Miinchen, 23 Band 1 Heft, pp. 53-76. or 3 55 OLSSON: PERUVIAN MI0cENE graphic belts of Hubach through Panama and south through the coast region of Ecuador and Peru. In Ecuador these physio- graphic provinces are well defined but they cannot be continued directly south of the Gulf of Guayaquil. The Coast Range rough- ly paralleling the Ecuadorian coast begins at Atacames in the Montanas de Atacames and extends south forming the divide be- tween the short streams flowing directly into the Pacific and the eastern drainage of the Rios Esmeraldas and the Guayas. At the south, the Coast Range is formed by the Cordillera de Col- onche which curving strongly to the east passes into the Cordil- lera de Chongon. The Cerros de Zaptoal and the Cerros de Chan- duy extending south into Punta Posorja should probably be in- cluded in the Coast Range as they separate the Miocene deposits of the Aquada basin from the older Tertiaries of Santa Elena. The shore-facies of the Chanduy conglomerates lends further support to this view. The Pacific depression covers the drain- age basin of the Rios Esmeraldas and the numerous branches of the Guayas and Rio Daule flowing southward into the Gulf of Guayaquil. It seems to end in the low mangrove swamp region of Rio Zarumilla and Jambeli near the Peruvian border. The Pacific depression of Ecuador as just noted, terminates near the Peruvian border through the southeastward swing of the Cordillera de Colonche and Chongon, and the Cerros de Chanduy. A similar condition but in reverse position is seen further south in Peru and in the Sechura desert: the recognition of a Coast Range and a Pacific Depression or physiographic features homologous to those north of the Gulf of Guayaquil is again possible. The Cordillera de Amotapes is a subsidiary spur of the Andes trending southwest from the knot of Loja. The Amotapes end in Cerro Prieto (elevation 3,000 feet) just east of Negritos but the range may be continued to the southwest and south through the slate and granite mountains of Paita, the Cerros de Illeascas and the Lobos Islands. The continuation of the Coast Range is difficult to follow further south as this region lies submerged off the coast of Central Peru. Lisson*+ however, believed that the Illescas and the Lobos 54Lisson 1925, Como Se Genero El Suelo Peruano. Bol. de la Soe. Geol. del Peru, Tomo I, pp. 97-126. 56 BULLETIN 68 56 Islands formed part of an old mountain chain which formerly connected with the Paracas Peninsula and continued along the coast to Mollendo. This range, Lisson has named the Cordillera de la Costa. Steinmann believed that the Cordillera de la Costa was formerly part of a continental massive lying off the Peruvian coast (the Macizo de la Costa del Pacifico). The Sechura desert and its southward extension in the submerged zone between the Illescas and Paracas thus corresponds to the Pacific Depression of Hubach in western Colombia and like it probably bordered the eastern margin of a Pacific land mass. This interpretation is the same as advanced by Troll in his paper referred to above. The northern termination of this province is located in the Chira valley or to the southeast of the Amotape mountains. while the delta-shaped area lying to the north of these mountains and to the south of the Cordillera de Colonche is a separate physio- graphic province and includes the older Tertiary formations (Lower and Middle Eocene deposits) of Peru and Santa Elena. The probabilities that Panama and western Ecuador were land in Cretaceous times has been noted. During the Tertiary, this region was partly downfolded in the formation of the Bolivar geosyncline. That Panama remained land during Tertiary time is indicated by the marginal or shore character of its Tertiary de- posits except those of the Chiriqui Lagoon in northwestern Pana- ma which belong with the Tertiary region of northern Costa Rica and probably the Tertiary deposits of the Darien region of east- ern Panama. There are no important areas of Tertiary sedi- ments around the shores of the Bay of Panama or on the Pearl Islands. There is a large area of Miocene rocks in the Tuyra- Chucunaque basin which may include the Tertiary deposits of Garachiné but these deposits are Caribbean rather than Pacific in origin. In Veraguas and in southern Panama west of the Los Santos peninsula there are extensive deposits of Tertiary forma- tions but like those of the Canal Zone they are marginal or shore- facies rocks. Panama Bay is apparently of recent origin. The evidence although necessarily fragmentary, indicates that in Ter- tiary times, the Bolivar geosyncline was bordered on the west by land which included most of eastern Panama, and extended southward over the present site of the Gulf of Panama to west- 57 OLSSON: PERUVIAN MIOCENE 57 ern Ecuador, its eastern shores being the Cordillera de la Costa or Coast Ranges of Colombia and Ecuador and its western shores, the southward extension of the Los Santos Peninsula. With the exception of the Santa Elena peninsula and the coast region south of Manta or Cabo San Lorenzo, the geology of western Ecuador is poorly known. In the coast section or the region west of the Coast Ranges, the Tertiary formations are of Upper Eocene to Upper Oligocene in age but Miocene deposits are apparently absent. On the Santa Elena peninsula, Miocene rocks are known only east of the Chanduy hills where they have an extensive development in the Amen - Aquada basin and are underlain by Upper Eocene - Upper Oligocene beds. From Amen and Aquada they extend north into the Daule basin to near Jipijapa, and there is great probability that they underlie the entire region north to Esmeraldas and northward into western Colombia. During the Miocene, the coast region of western Ecuador, as already remarked by Sheppard®®, was land while marine deposition was taking place in the Pacific depression or between the Coast Ranges and the main Andes. The shores of the land lying west of the Bolivar geosyncline were invaded by the sea during the Upper Eocene and Upper Oligocene periods thus accounting for the older Tertiary formations in the coast section of western Ecuador. The Miocene rocks of Ecuador pass southward and appear in northern Peru at Zorritos and Tumbez. As previously mentioned, the Zorritos Miocene does not extend south of Piedra Redonda or connect directly with the Miocene region of the Sechura des- ert. These two districts were separated by land or a coastal bulge which extended from the Cerros de Paita north past Negritos, Cabo Blanco, Mancora to Piedra Redonda. Spieker’s conclu- sions drawn from his paleontological study of the Zorritos fauna that such a barrier or point of land must have existed to account for the lack of relationship between the Zorritos fauna and those of Chile has been substantiated, Berry accepted this view but seems to place this land barrier to the south of the Illescas. 55Sheppard 1928, Notes on the Miocene of Ecuador, Bull. Amer. Assoc. Petroleum Geologists, vol. 12, p. 672. 58 BULLETIN 68 58 In Oligocene and early Tertiary times, conditions were quite different. The very extensive distribution of the Upper Eocene and Upper Oligocene deposits from Sechura north through Ecuador and Colombia show complete submergence of the Bolivar geosyncline together with more or less flooding of its margins. Courty’s®® interesting record of Natica crassatina Lam- arck (probably Ampullinopsis spenceri Cooke) near Santiago, Chile, and representing a horizon of Stampian or Middle Olig- ocene age shows the extension of the Punta Bravo fauna of northern Peru southward into central Chile and that open water communication existed along the entire west coast of South America during the later half of the Oligocene. On physiographic as well as structural grounds, the Bolivar geosyncline can therefore be traced and reconstructed from northern Colombia to southern Peru and possibly into Chile. In- cidentally it may be noted that there is no evidence of a trunca- tion of the structural grain of South America as remarked by some writers nor is there any radical departure from the Pacific type of coast-line as originally defined to Suess. TERTIARY WGmRATNS AND CLIMATE Unlike the Tertiary Mountains situated along the Mediterran- ean and Caribbean mesogeosynclines the Andean region was not invaded to any great extent by marine waters during the Tertiary period and consequently the only Tertiary deposits known within the Andes proper are of fresh-water or con- tinental origin (see Steinmann®’). These mountains were therefore definitely uplifted at the close of the Cretaceous epoch, the Tertiary formations along their base being coastal de- posits, or extending as embayments along the main valleys, gradu- ally passing into non-marine deposits as shown by Anderson’* and others in northern Colombia. If the Andes had existed as com- paratively low mountains during the early Tertiary, a much great- er extension of these deposits would be expected than is now 56Courty, George., 1907, Exploration Géologiques dans l’Amerique du Sud. Mission Scientifique. G. De Créqui Montfort et E. Senechal de la Granze. Paris. p. 12. 57Steinmann 1922, Uber die junge Hebung der Kordillera Siidamerika. Geol. Rundschau vol. 18, p. 1. 58Anderson 1927, Nonmarine Tertiary deposits of Colombia, Bull. Geol. Soc. America, vol. 38, p. 598. 59 OLSSON: PERUVIAN MIOCENE 59 known to be the case. — As noted by Steinmann®®, the marine Tertiary deposits of the coast have not been uplifted to any great height. In the Tumbez region of northern Peru, the highest hills have an elevation be- tween 1,800 to 2,000 feet. Small remnants of Upper Eocene lime- stones cap a few of the slate mountains of the Cerros de Illescas at an elevation of about 1,200 feet but the Illescas are locally up- lifted, fault-block mountains. Elevations in the Tertiary region of northern Colombia and western Ecuador are not known but it is extremely doubtful that any of the Tertiary hills exceed 3,000 feet in elevation. The Tertiary deposits of northern Peru, Ecuador and Colom- bia are remarkably similar, showing that conditions of sedimenta- tion and denundation were essentially the same through this large region. Thick, coarse deposits, often with volcanic material, al- ‘ernate with shales and other fine-grained rocks. The coarse deposits usually follow a stratigraphic break of greater or less importance and indicate uplift followed by greatly increased erosion and volcanic activity in the coast lands. It seems probable that these periods of partial draining of the Bolivar geosyncline were contemporaneous with considerable uplift of the neighbor- ing Andes from which most of the material forming the Tertiary clastics of this region have come. On the basis of this evidence, the Andes were probably moderately high mountains during the following periods. First: during the late Middle Eocene, corresponding to the deposition of the Parinas and Restin sand- stones in Peru. Second: during the early Oligocene probably reaching their greatest height during the early Middle Oligocene (the Mancora episode). Third: during the Lower Miocene or about the same time as the deposition of the Lower Zorritos sandstones and the Variegated beds. Fourth and fifth: during the early Pliocene and Recent. During the periods of general marine transgression in the coastal region, usually accompanied with shale deposition, the Andes were probably much lower. In the late Eocene, late Oligocene and middle Miocene the Andes were lower than in the intervening periods. Remains of fossil plants such as leaves and fruits have been discovered at several horizons in the Tertiary deposits of north- 59Steinmann 1922, op. cit. p. 1. 60 BULLETIN 68 60 ern Peru and Ecuador. Professor Berry®? who has described these fossils, finds that they belong to forms or types character- istic of the humid low-land tropics or in Chapman’s terminology to the Humid, Tropical Life Zone. In his earlier papers, Profes- son Berry explained the evidence from these fossil florules as indicating that during most of Tertiary times, the Andes were not sufficiently high to prevent the moisture-bearing trade winds from reaching the coast. In his last contribution to this subject written after a personal visit to this region following the climatic upset of 1925-26, Professor Berry admitted that he had perhaps unduly stressed the importance of the trade wind factor operative in the absence of a high divide on the climate of Tertiary time. Although the exclusion of the trades from the West Coast by the high wall of the Andes may be a factor in determining the climate of this region, it is very doubtful that the absence of for- est growth along the northern Peruvian coast can be attributed to this cause alone. On the other hand the influence of the Hum- boldt or Peruvian Current on the climate of Peru and Chile is enormous and it is due to its presence more than any other cause that the Peruvian desert owes its intense aridity. A humid Ter- tiary flora in northern Peru flourishing at a time when the geog- raphy of this region was so different from what it is today, can- not be considered as sufficient evidence to indicate that the Andes were continuously low until late in Tertiary times. With exception of the land breezes in the morning which Ulloa® in 1748 described under the name of Terrales, the winds in northern Peru blow regularly and strongly from the south and southwest or from the sea over the land. As these cold winds encounter a warmer land surface they are cooling and drying in their effect and carry what little moisture they have as fog or garua, or later precipitated as rain along the higher slopes of the Andes. The aridity is always most intense on the coast points 60Berry 1924, Am. Jr. Sci., vol. 8, pp. 123-126; 1927, The Pan-American Geologist, vol. 47, pp. 128-132; 1929, Early Tertiary fruits and seeds from Belen Peru, The John Hopkins University, Studies in Geology, No. 10, pp. 139-172, pls. 1-8. 1929 An Eogene tropical forest in the Peruvian Desert. Proc. Nat. Acad. Science, vol. 15, pp. 345-346. 61Ulloa 1748, Relacion Historica del Viaje a la Americana Meridional hecho de orden de S. Mag. para medir algunos grados de Meridiano etc., Madrid. Lib. 2, Cap. 1, p. 428. 61 OLSSON: PERUVIAN MI0cENE 61 which comes under the fullest effect of the cold winds from the sea. In the latitude of Paita and Piura, the country becomes progressively warmer and less desert inland as shown by the increase of plant growth until along the slopes of western Andes it passes into a humid forest growth above Palamba as described by Chapman®. At Cabo Blanco and Punta Parinas, the main body of the Hum- boldt Current leaves the Peruvian coast, swinging northwesterly into the Pacific but as shown by Wolf, a narrow arm continues northward along the coast of Ecuador. From Cabo Blanco north, there is immediately an increase in plant growth with mangrove swamps appearing at Tumbez and along the Guayas river. The western points of Ecuador such as Santa Elena, San Lorenzo and Cabo Pasado are arid as they still lie under the influence of the cold winds from the Humboldt Current but the interven- — ing stretches are quite humid. In his Geography and Geology of Ecuador, Wolf**, expressed his views on the part played by the Humboldt Current in giving rise to the desert climate of Peru and Ecuador as follows: “The influence of the sea on the littoral climate is so great that it can be affirmed without hesitation; ex- tend the Antarctic Current with its low temperature to the Gulf of Panama and it would soon convert the coast of Ecuador and Colombia into a desert similar to that of Peru; on the other hand, give the Peruvian coast a tropical sea with normal temperature, and it would soon change the aspect of the coast and the western Andes, covering them with a vigorous growth of vegetation nour- ished by regular, solstitial rains.” Guppy** came to the same conclusions as those of Wolf regarding the effect of the Hum- boldt Current in producing the desert climate of the West Coast. He described particularly the reappearance of patches of aridity along the Ecuadorian coast while in the interior of the Gulf of Guayaquil no longer subjected to the cold waters of the Hum- 62Chapman 1926, The Distribution of Bird-Life in Ecuador, Bull. Am. Mus. of Nat. Hist., vol. 55, p. 79. 63Wolf 1892, Geografia y Geologia del Ecuador, p. 387. 64Guppy 1906, The Humboldt or Peruvian Current and the Climate of the West Coast of South America in “Observations of a Naturalist in the Pacific, vol. 2, Plant Dispersal, pp. 490-498. 62 BULLETIN 68 62 boldt Current, a littoral flora flourishes that so far as mangrove is concerned is probably unrivalled in the world. Lately Dr. Murphy® who has made extensive biological studies along the coast of Peru and Ecuador, has also attributed the desert climate of this region, primarily to the influence of the Humboldt Current and is attending upwellings of cold submarine waters close to shore. The occurrence of a humid, low-land Tertiary flora in north- ern Peru does not therefore have a great bearing on the height of the Andes in Tertiary times but it does indicate the absence of the north branch of the Antarctic drift from the coast of Peru at that time. The Humboldt Current seems to have made its appearance along the West Coast in the Pliocene. As early as 1848, the French Engineer Domeyko®® concluded from his studies of the physical characteristic, mode of deposition and the absence of plant remains in the Tertiaries of Coquimbo, that these beds had been formed under rainless and arid conditions similar to those now prevalent in northern Chile. The Coquimbo beds as previously indicated are probably late Pliocene in age and about equivalent to the Mancora tablazo. During the for- mation of the Mancora tablazo deposits, the evidence available does not indicate an arid climate in northern Peru. As shown by Guppy, the distribution of the Mangrove-swamp vegetation of Ecuador has a direct relationship to annual rainfall. At the present time, mangrove finds its southern limit at Tumbez. There are several species of mollusks which are restricted to a Man- grove-swamp habitat, amongst which is Arca (Senilia) grandis Broderip and Sowerby, the Pata de Burro of the Peruvians is the most important. In the recent fauna, the southern limit of this species is Tumbez. Arca grandis is a common fossil in the Peruvian tablazos and its distribution is therefore a guide to the former, greater extension of mangrove-swamp conditions during Pleistocene and late Pliocene times. Along the south shore of the Bay of Sechura east of Bayovar, the fossil shells of Arca 65Murphy 1925, Oceanic and Climatic Phenomena along the West Coast of South America during 1925, Geog. Review, vol. 16, pp. 26-54; also The Humboldt Current in “Bird Islands of Peru” Chap. 8; also Chap- — man, The Distribution of Bird-Life in Ecuador, op. cit., pp. 29-31. 66Domeyko 1848, Sur le terrain tertiaire et les lignes d’ ancien niveau de VOcean du Sud, aux environs de Coquimbo (Chile). Annales des Minas, 4th series, tome 14, pp. 153-162. 63 OLSSON: PERUVIAN MI0ocENE 63 grandis washed from cliffs of Pleistocene sands, cover the upper part of the beach. The range of this species was therefore much more extensive in Pleistocene times than at present and a cli- mate at least as humid as that of Tumbez existed in the Sechura district or approximately 200 miles beyond the present southern limit of Mangrove vegetation. In its plant-life, the Peruvian desert shows signs of its recent origin in that only a few species have as yet acquired adaptations fitting them for a desert environment while the flora as a whole is merely the southern marginal extension of the semi-arid equa- torial plant-zone of western Ecuador. The continued sinking of the coast of south ofUlescas and steepening of the continental slope by faulting is probably resulting in stronger upwellings of cold submarine waters along the shores and consequently as be- lieved by Wolf and others, the aridity of northern Peru and west- etn Ecuador is gradually increasing. SYSTEM AMICs DESCRIP LION OF MIOCENE MOLLUSKS OF NORTHERN PERU Class PELECYPODA Order PRIONODESMACEA Superfamily NUCULACEA Family NUCULANIDZ Genus NUCULANA Link Subgenus SACCELLA Woodring Nuculana (Saccella) peruviana Dall Leda acuminata Nelson, 1870, Trans. Conn. Acad. Sei., vol. 2, p, 205, pl. 7, fig. 8. (not von Buch, 1845). Leda peruviana Dall, 1895, Trans. Wagner Free Inst., vol. 3, pt. 4, . 579. ee Brown and Pilsbry, 1911, Proe. Acad. Nat. Sei. Phila., vol, 63, p. 362, pl. 27, fig. 8. Leda peruviana Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 93, pl. 5, fig. 1. Original description.—Shell oblong. Anterior margin slightly produced, 64 BULLETIN 68 64 but rounded; posterior produced and acuminate. Umbos prominent, very convex above, incurved below. Surface marked by broad, flat ribs, sep- arated by narrow, but well marked spaces. Hinge line slightly curved; teeth numerous and subequal. Shell slightly depressed posteriorly, forming indistinct angulations with the lateral margins. Three specimens measure as follows: Length, 6.2 millim, Breadth, 11.6 millim, Height, millim. D2) 10.8 YY 29) 20,0 a) 3} 9) 8,2 9) co las2 a ID Bil 4 eS a8 » — Nel- son, 1870. Remarks.—The material we have of this species is not satis- factory nor abundant. The shell becomes quite large, an imper- fect specimen in our collection would measure about 25 milli- meters in length if perfect. The sculpture consists of coarse, even, concentric riblets separated by deep, incised lines. The escutcheon is elongated, elliptical and marked with fine, parallel lines. A narrow, smooth band borders the anterior side of the umbonal ridge so that the posterior extremity appears weakly biangled or rostrated. As pointed out by Spieker, Leda balbo@ Brown and Pilsbry from Gatun is probably identical with peruwviana. Brown and Pilsbry’s figure show the long, anterior side and weakly bicari- nate posterior end and coarse sculpture of peruviana. The recent N. elenensis Sowerby is very similar to the smaller specimens of peruviana but has a shorter and more strongly contracted poste- rior side. Locahty and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Superfamily ARCAEA Family ARCIDZ Genus ARCA Linné Subgenus DILUVARCA Woodring Area (Diluvarca) vanholsti Spieker Arca (Scapharea) vanholsti Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 106, pl. 5, fig. 14. Original description—Shell small, thin, only moderately inflated, of slightly elongated rhomboidal shape, inequilateral, Base elliptical. An- terior end rounded, the margin sloping posteriorly in an even curve from the hinge-line, with which it forms approximately ‘a right angle. Posterior 65 OLSSON: PERUVIAN MIocENE 65 margin produced beyond end of hinge-line, with which it makes an incident angle of about 133°. Beaks not prominent, situated near anterior third of length, suleate near apex, the ribs anastomosing into the suleus, and the suleus dying out entirely on the main slope of the shell. Umbonal slope widens rapidly from apex of beaks, curving in even contour anteriorly and forming a perceptible keel posteriorly. Ribs, 23 in number, not suleate, square in shape over the entire length of the shell, with interspaces wider than the ribs mesially, vice versa on posterior wing and extreme anterior end, Ribs show growth-lines which in places tend to form nodes, but no distinet or regular quadrisection is evident to the naked eye. Microscopic examination reveals an irregular but distinct nodosity. Cardinal area low and narrow, with elevated margin behind the beaks, and with two valve-like furrows. Teeth small, fine, vertical. Inner margin fluted. Length, 16; altitude, 10.25; semi-diameter, 5; length hinge, 12.5 mm.—Spieker, 1922. Remarks.—Our collection contains three specimens of an Ark from Zapota!l which are probably this species. They are poorly preserved, being changed to gypsum so that the ornamentation of the ribs has been completely lost. Arca vanholsti resembles A. dariensis in shape but differs ac- cording to Spieker’s description in having 23 ribs instead of 30 and the ribs are simple and not sulcated as in the Panama species. Our largest specimen has a length of about 30 milli- meters. Locality and Geologic Occurrence.—Lower Zorritos, Que. Za- potal; Que. Hervideras near Boca Pan (Spieker). Area (Diluvarca) spiekeri, n. sp. Plate 2, figs. 2, 3, 6 Shell small, subquadrate, solid; umbones wide, ending in the small, inconspicuous beaks situated at the anterior one-quarter ; there is a feeble sulcus across the middle of the beaks, very wide, shallow and scarcely discernable on the umbones but forming a wide, shallow inflexion along the posterior half of the ventral margin; umbonal ridge pronounced, more or less angled and with the posterior submargins slightly convex; when viewed from within, the ventral and dorsal margins are seen to be paral- lel, the anterior side rounded in the lower or ventral half and the posterior side distinctly arched in the middle; sculpture not similar on the two valves, the ribs of the left valve finely beaded while those of the right valve are smooth except the most anterior set and near the ventral margins; the interspaces are quite wide, flat and usually finely and regularly etched by the growth-lines; hinge area long, narrow, smooth except for a single, asymmetrical, inverted V-shaped groove; hinge teeth 66 BULLETIN 68 66 forming a nearly continuous series of numerous, closely crowd- ed teeth; interior of shell deep, the margins fluted by the end of the ribs. Length 21 mm.; height, 17.25 mm.; semidiameter, 9 mm. (Holotype). Length, 19.50 mm.; height, 16.00 mm.; semidia- meter, 8.50 mm. (left valve). Remarks.—Specimens in our collection from the Upper Zor- ritos are larger, having a length of 26 millimeters but seem to be- long to the same species. This species may be related to Arca singewaldi Spieker but according to Spieker’s description, that species differs by its straighter posterior side and by its sulcated ribs. Locality and Geologic Occurrence.—Lower Zorritos of Zapotal and Que. La Cruz. Upper Zorritos, Zorritos. Arca (Diluvarea) valdiviana Grzybowski (not of Philippi) Arca valdiviana Grzybowski 1899, Neues Jahrb. f, Min. ete., Beil. Bd., 12, p. 632, pl. 18, fig. 1. (not of Philippi). Remarks.—Grzybowski’s specimen which he identifies with Philippi’s species from Chile was collected at Rica Playa. His figure shows a shell similar to the common Arca tuberculosa Sowerby of the recent Peruvian-Panamic fauna. This mollusk is commonly used as food and shells have been widely distributed over the coastal region of northern Peru by the aborigines and and natives. Arca valdiviana figured by Philippi® is an internal cast having a length of about 88 millimeters. It differs from tuberculosa and from the shell figured by Grzybowski, by its fewer ribs, pro- portionately greater length, the ventral margin is more nearly parallel to the hinge-line and the posterior extremity is pointed or cuneate. The ribs of valdiviana number about 32 while there are about 37 on Grzybowski’s shell. Berry’s®* record of Arca valdiviana from the Pleistocene of Zorritos, doubtless refers to A. tuberculosa. Locality and Geologic Occurrence.—Rica Playa. 87Philippi, 1887, Die Tertiaren und Quartaren Versteinerungen Chiles, p. 187, pl. 40, fig. 1. 68Berry, 1923, Pan-American Geologist, vol. 40, p. 18. 67 OLsson: PERUVIAN MI0cENE 67 Arca (Diluvarca) sechurana, n. sp. Plate 4, fig. 1 Shell of medium size, subquadrate, convex; anterior and ven- tral margins evenly rounded, the posterior portion generally becoming straighter and more or less parallel to the hinge-line ; posterior side obliquely subtruncate, straight to slightly curved and meeting the ventral margin at an angle a little less than go degrees; umbonal slope quite pronounced, rounded; umbones full, low with small beaks situated near the anterior one-fourth ; valves similarly sculptured, the ribs of the left valve being usual- ly a little wider and with narrower interspaces than those of the right; the ribs number about 36, there being about 10 on the posterior-dorsal slope and 26 on the rest of the shell; the ribs are square in section, nearly smooth or only faintly noded by the growthlines and often faintly grooved along the middle; hinge area long and narrow, and marked with 3 or 4 lozenge- shaped grooves. — Length, 38 mm.; height, 31 mm.; diameter, 24 mm. (Holo- type). Length, 35 mm.; height, 29 mm.; diameter, 24 mm. Length, 37 mm.; height, 31 mm.; semidiameter, 12.50 mm. Remarks.—This species is probably related to Arca tuberculosa Sowerby but is distinguished by its different shape, the posterior side being less depressed and spreading as well as its greater convexity. Locality and Geologic Occurrence.—Upper Zorritos of Punta Picos. Montera formation, Bayovar (common). Arca (Diluvarca) columba, n. sp. Plate 1, figs. 2, 6 Shell large and strongly convex ; umbones high, wide and full passing into the small, curved beaks situated at the anterior one- fourth; the umbonal ridge is strong with a sharply contracted posterior-dorsal slope which is slightly convex or vaulted in the middle, forming an arched or angled posterior margin; ribs of the two valves not quite the same; on the right valve there are about 41 ribs, 15 on the posterior-dorsal slope and 26 from the umbonal ridge to the anterior extremity; on the middle of this valve, the ribs are narrow, widening and becoming double or mesially grooved near the ventral margin; the interspaces are flat and nearly twice the width of the ribs; on the anterior-submargins, the ribs are wider and double over a greater length; those of the posterior-submargin similar or divided by 4 or 5 small rib- 68 BULLETIN 68 68 lets in the center; when well-preserved, the ribs of the left valve are finely noded on the umbonal region; ribs on the left valve similar to those of the right, but remain simple except those on the anterior and posterior submargins which become double or further subdivided; cardinal area of moderate width, grooved. Length, 53 mm.; height, 52 mm.; diameter, 48 mm. Remarks.—This species is very distinct from the other fossil Peruvian Arks. It recalls the Arca veatchi Olsson® of the Cen- tral American and Colombian Miocene but differs by its higher, fuller umbones, its angled posterior-dorsal side but mainly in the sculpture and form of its ribs. In veatchi, the ribs of the right valve are flat-topped and separated by deep, narrow interspaces. In the Peruvian species, the ribs of the right valve are narrow with wide interspaces. On the left valve of veatchi the ribs are wider, more strongly beaded and do not become mesially divided. The cardinal area is wider in columba, the umbones more anterior in position and the umbonal ridge sharply angled. Arca columba together with Arca dariensis, Pitaria tumbezana, Dosinia delica- tissima and Turritella altilira occur in the upper Cardalitos shales at Sechurita near the mouth of Quebrada Grillo. The shells are usually heavily encrusted with gypsum. Locality and Geologic Occurrence-—Cardalitos formation, Que. Grillo, Sechurita. Area (Diluvarea) dariensis Brown and Pilsbry Arca oronlensis Dall. 1898, Trans. Wagner Free Inst. Sei., vol. 3, pt. 4, p. 658, Not of Gabb. Arca dariensis Brown and Pilsbry. 1911, Proe, Acad, Nat. Sci. Phila., vol. 63, p. 362, pl. 22, fig. 10. Area gatunensis Toula, 1911, Jahrb. der K-K Geol. Reichsanstalt, vol. 61, p. 498, pl. 30, fig. 4. Arca (Scapharea) dariensis Olsson, 1922, Bulls. Amer. Pal., vol. 9, p. 356, pl. 22) figs. 10-13. Arca (Scapharea) dariensis Maury, 1925, Bulls. Amer. Pal., vol. 10, p. 207, pl. 6, fig. 5. Arca (Scapharca) dariensis Anderson, 1929, Proe. Calif. Acad. Sei., 4th series, vol. 18, p, 147. Original description.—The shell is long (the alt, six-tenths of the length), basal and upper margins subparallel, beaks, small, at the anterior two- sevenths of the length. Valves not quite equal, the left slightly surpassing the other along the basal margin. Sculpture of about 31 radial ribs. In the median part of the valves these ribs are narrower than their intervals, In the left valve the ribs are closely nodulous in the lower part, very shortly scaly near the beaks. Towards the two ends the ribs widen and become 69O]sson, 1922, Bulls. Amer. Pal., vol. 9, p. 361, pl. 23, figs. 1-3, 69 OLSSON: PERUVIAN MiocENnE 69 divided by a median groove, on both sides of which it becomes nodulose, and the intervals are crossed by their lamelle. In the right valve the ribs are smooth in the middle field, the intervals concave, with concentric lamelle towards the beaks. At both ends the ribs are wider and divided by a groove, as in the other valve. In both valves the anterior ribs have shallow sulcus, the posterior ones a distinct narrow furrow. The ligament area is narrow, lanceolate, marked with two or three grooves diverging at a wide angle. The teeth are very fine and close, about 70 in a shell 36 mm. long. Interior radially striate, the margin crenulate as usual—Brown and Pilsbry, 1911. Remarks.—A small Ark probably identical with the common Arca dariensis of the Canal Zone occurs in the upper Cardalitos shales at the mouth of Quebrada Grillo at Sechurita. The speci- mens are poorly preserved and more or less encrusted with gyp- sum so that they cannot be adequately figured. They have about 30 ribs which are sulcated on the anterior and posterior ends of the valves as characteristic of dariensis. Locahty and Geologic Occurrence.—Cardalitos formation, Que. Grillo at Sechurita. Section CUNEARCA Dall Arca (Cunearca) thalia, n. sp. Plate 2, figs. 7, 8, 9 Shell small or moderate size, solid, high, trigonal; valves discrepant in sculpture; left valve with high, prominent umbone, a strong, umbonal ridge and flattened to impressed, posterior- dorsal slope; ventral side nearly parallel to hinge line, the ante- rior side smoothly rounded, the posterior, obliquely subtruncate becoming cuneate at the posterior-ventral extremity; right valve similar but less solid in appearance than the left and with nar- rower ribs and correspondingly wider interspdces ; ribs of the left valve number about 25, there being about 16 on the anterior side of the umbonal ridge and 9 on the posterior-dorsal slope; the ribs on this valve are strong, moderately high, square in section and separated by deep, grooved, smooth interspaces; the ribs on the anterior-ventral portion are strongest and tend to become wider near the margin; they are coarsely noded over the entire left valve; on the right valve, the ribs are narrower and with wider interspaces ; the first set of 8 from the hinge line across the anterior side are quiet large and coarsely noded; of this set, the first 4 are simple while the other 4 are wider and tend to become double near the ventral margin; there are 8 or 9 ribs across the middle of the valve.to the posterior-dorsal ridge, 70 BULLETIN 68 ei 70 these are narrower than the anterior set, simple, the first 4 or 6 more or less noded, the others nearly smooth; there are about 8 ribs on the posterior-dorsal area, these are small, widely separa- ted and generally feebly beaded; cardinal area asymmetrical and subtrigonal in shape and fairly wide, smooth except for a V-shaped groove, its apex lying just posterior of the beaks; hinge teeth divided into two unequal series, there being about 26 narrow teeth in the posterior set and about 18 in the anterior. Length, 19.5 mm.; height, 17 mm.; semidiameter, 9.5 mm.; (left valve). Length, 16.5 mm.; height, 15 mm.; semidiameter, 8 mm.; (right valve, Holotype). Locality and Geologic Occurrence.—Lower Zorritos, Que Za- POtaly team Crtz Area (Cunearea) zorritensis Spieker Plate 4, figs. 3, 5, 11 Scapharca sp. ind. Nelson, 1870, Trans. Conn. Acad. Sei., vol. 2, p, 205. Arca (Cunearca) zorritensis Spieker, 1922, John Hopkins University, Studies in Geology, No. 3, p. 96, pl. 5, figs. 4, 5. ? Arca (Scapharca) pantheonensis Spieker, 1922, op. cit., p. 99, pl. 5, NOSSO) Original description.Shell of moderate size, high, trigonal marginally cuneate in cross-section. Anterior margin rounded, descending abruptly into the ventral margin, which continues to descend almost to the posterior extremity of the shell, whence the posterior margin rises abruptly in an elliptical curve. Umbones erect, submedian in position, slightly proso- gyrate, inflated. Anterior surface smoothly convex, the valves meeting at an acute angle; median surface convex; posterior surface somewhat excavated behind the beaks, with a very gentle carina descending from the beaks and flattening towards the posterior marginal angle, At the marginal junction of the valves the surfaces are somewhat attenuated, the form being wedge-like. Sculpture of 25 low, squarish ribs, marginally nodulose over the entire length of the left valve, on the right valve slightly nodulose anteriorly, smooth posteriorly; upper sculpture of both valves unknown. Interspaces slightly wider than ribs anteriorly, equal mesially and posteriorly, crossed by fine concentric lines. Area lanceolate, smooth, bounded by a distinet, fine marginal furrow. Teeth, visible in cross-section as joined valves are viewed from above, fine mesially, coarser distally, Inner shell unknown. Length, 16.25; height 15.5; diam., 12.5 mm. —Spieker, 1922. Remarks.—This shell is quite common at Tucillal but like the type specimen from the Nelson collection on which Spieker based this species, the external surface and ribs are exfoliated on the umbonal region. The form is a true Cunearca with dis- crepant sculptured valves. The right valve has 23 to 24 square- topped ribs between flat interspaces of the same width as the ribs. The anterior set of 7 or 8 ribs are regularly noded, the nodes being elongated across the ribs; the following 8 to the 71 OLsson: PrruvrAN Mtocenié 71 middle of the umbonal ridge are smooth, succeeded by 9 or 10 on the posterior-dorsal slope which are progressively smaller, smooth, except the most posterior set of 4 or 5 which are feebly noded. The left valve has usually 26 ribs with 18 on the anterior side of the umbonal ridge and 8 on the posterior side. All the ribs are noded on this valve. From recent Arca (Cunearca) nux Sowerby of the Peruvian coast, zorritensis differs by its more strongly noded ribs of the left valve. Length, 22.5 mm.; height, 21 mm.; semidiameter, 9 mm.; (right valve). Length, 19.5 mm.; height, 17 mm. ; semidiameter, 8 mm.; (right valve). The specimen on which Spieker based this species is much smaller than the shells measured above, the holotype having a length of 16.5 milimeters. The Arca (Scapharca) pantheonensis Spieker is a Cunearca with discrepantly sculptured valves and nearly smooth cardinal area. Except in size it does not differ sufficiently in form or sculpture to be considered as a separate species. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Que. Pantheon. Subgenus SENILIA Gray Arca (Senilia) chiriquiensis var. toroensis Spieker Plate 1, figs. 3, 4 Arca (Anadara) toroensis Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 121, pl. 6, figs. 9, 10., pl. 7, figs. 1. Arca (Anadara) toroensis var. crassa Spieker, 1922, op. cit. p. 124, pl. 7, fig. 2. Arca (Anadara) toroensis var. prolata Spieker, 1922, op. cit., p. 125, pl. 7, fig. 3. Arca (Scapharea) crescens Spieker, 1922, op. cit., p. 116, pl. 6, figs, 3, + Arca (Scapharca) imporcata Spieker, 1922, op. cit., p. 113, pl. 5, figs. Arca (Anadara) nelspni Spieker, 1922, op. cit., p. 119, pl. 6, figs. 7, 8. Original description.—Shell large, heavy, inflated. Anterior margin broadly rounded, forming a right angle with the hinge-line; ventral margin gently rounded, its flattest part being usually nearly parallel to the hinge-line, in some specimens descending slightly posterior. Posterior margin produced and rounded more acutely than the anterior margin, forming an angle of 142° with the hinge-line. Umbones high, almost uni- formly 14 mm. above the hinge, situated at about the anterior third oi the entire length, rounded in out-line viewed laterally, with the upper surface sloping distinctly forward in some mutants, and symmetrically erect in others. Umbonal slope dome-like anteriorly, circular in eross- section mesially, and with a distinet surficial keel running from the poste- rior side of the umbone to the posterior margin at an angle of about 45°. 72 BULLETIN 68 he The keel is flared in some forms, forming a distinct shoulder parallel to the margin, Ribs 28 in number, (29 on some left valves) prominent, rounded, with interspaces slightly more than twice as broad as the ribs (largest ribs 1 mm.; interspaces 2.2 mm.) showing growth-lines prominent- ly near the ventral margin, and noded irregularly, the nodes being knob-like. Area high and broad, with wave-like imbricated furrows increasing in distance of separation from the hinge-line to the beak and more sinuous above, Teeth small and short, numbering about 85, set on a thin hinge plate 36 to 40 mm. long, becoming more widely separated and coarser distally, CECB) vertical length of anierior teeth 2.5 mm.; of posterior teeth, 2.75 mm.; of smallest tooth 1 mm. Interior margin regularly and deeply fluted. ae en of two specimens: length 50; height 47.5; diameter, 24.5; length, 47; height 42; diameter 20.—Spieker, 1922. Remarks.—A group of Arks closely related to Arca chiriqui- ensis Gabb of the Caribbean Miocene, is the most common fossil type in the Zorritos rocks. They have been divided by Spieker into several species and varieties. As far as our collection goes, only three forms can be recognized and these are very likely connected by transitional types. Most Senilias favor the brack- ish-water environment of Mangrove swamps and lagoonal situ- ations and for this reason they are more subject to extreme vari- ation in form, shell thickness and sculpture than usually seen among the typical marine species of Arca. : The most typical of the group is the toroensis of Spieker. It is characterized by its strongly humped valves, the greatest con- vexity of the shell located just anterior of the middle with a shallow but distinctly contracted zone extending from the beaks to the posterior half of the ventral margin. The ribs number about 28 to 31. The ventral margin is straight and nearly parallel to the hinge-line. Cardinal area high and marked with numerous, crowded, lozenge-shaped grooves. The ribs are usually more or less noded on the anterior portion of the valves while they are narrow and plain on the posterior half of the middle. Typical chiriquiensis’® from Panama and Santo Domingo are very similar to toroensis but usually differ by their shorter more solid shell and less numerous, heavier ribs. Woodring’s” figures in the Hai- tian report are very similar to our specimens of toroensis. Length, 62.50 mm.; height, 53.50 mm.; semidiameter, 30.00 mm. Length, 50.00 mm.; height, 40.00 mm.; semidiameter, 40.00 mm. 70Gabb, 1861, Proc. Acad. Nat. Sci. Phila., vol. 12, p. 567. Pilsbry, 1922, Proc. Acad. Nat. Sci. Phila., vol. 73, p. 405, pl. 40, figs. 2-6; pl. 41, figs. 1-3. 71Woodring, 1924, Geology of the Republic of Haiti, pl. 16, figs. 6-8. ~j 73 OLsson: PERUVIAN Miocr: & Locality and Geologic Occurrence.—Variegated beds, P. Picos, Que. Heath. Upper Zorritos, P. Picos, Que Grillo (Spieker) Zorritos, Que Toro, Tijeritas (Spieker). s Arca (Senilia) ‘chiriquiensis septifera Grzybowski Plate 1, fig. 5 Arca septifera Grzybowski, 1899, Neues Jahrb. f. Min, ete., Beil. Bd., 12, p. 633, pl. 18, figs. 2, 2a. Arca (Anadara) septifera Spieker, 1922, Johhs Hopkins University, Studies in Geology, No. 3, p. 117, pl. 6, figs. 5, 6. Original description.—Die Schale ist sehr dick und hoch gewirbelt. An den horizontalen Schlossrand stosst fast senkrecht der Vorderrend, der gegen unten in den bogenférmigen Stirnrand tibergeht. Der Hinterrand bildet mit dem Schlossrand einen stumpfen Winkel. Die im Verhaltniss zu der dicken Schalenwand diinne Schlosskante ist durch eine septumartige, in der Mitte liegende und tief in die Wirbelhohle eingreifende Falte gestiitzt. Die hohen, nach unten gekriimmten Wirbel stehen in 1/3 der Lange kaum 10 mm von einander entfernt. Die hohe, gewolbte Area ist wellenformig gestreift; ihr hinteres Ende tragt einige senkrecht zum _ Schlossrand stehende Leistchen. Die Oberflache ist mit 28 erhabenen, starken, gegen den Stirnrand knotenférmig verdickten Rippen verziert, Hohe 57 mm, Lange 62 mm, Dicke (einer Klappe) 30 mm.—Grzybowski, 1899, Remarks.—In this variety, the shell tends to become subcir- cular in form, the height and length being nearly equal. Grzy- bowski’s figured specimen is an imperfect left valve, the ventral margin having been broken away as seen by the thick shell and lack of the internal flutings of the ribs thus accentuating its sub- circular form. Grzybowski’s measurements indicate a shell much larger than the average size of toroensis. The septum shown in Grzybowski’s figure and basis of the name sepifera is probably not a constant feature. Such septa but rarely as large as that shown for septifera are frequently seen in various species of Arks such as Arca grandis, incongrua etc., lying along the lower or inner side of the hinge plate. Most specimens of chiriquiensis show this feature. The figured specimen is a shell with firmly cemented valves. The umbones are high, prominent and nearly central so that the valves are nearly equilateral. There are 28 to 29 ribs, those of the left valve being coarsely noded on the anterior half of the shell becoming smooth on the posterior side. Length, 62 mm.; height, 57 mm.; semidiameter, 30 mm.; (Grzy.). Length, 50 mm.; height, 46 mm.; diameter, 43 mm. Locality and Geologic Occurrence——Upper Zorritos, Punta Picos, Grau. 74 BULLETIN 68 74 Area (Senilia) chiriquiensis obesiformis Grzybowski Arca obesiformis Grzybowski, 1899, Neus Jahrb. f. Min. ete., Beil, Bd., 12, p. 633, pl, 18, figs. 8, 3a. Arca (Scapharea) obesiformis Spieker, 1922, Johns Hopkins Univer- sity, Studies in Geology, No. 3, p. 115, pl. 6, figs. 1, 2. Original description—Schale queroval mit zugestumpften Vorder-und verlangertem Huinterrande. Schlossrarid gerade, Area lang, breit, mit schwach angedeuteter Querstreifung tiber den dachformigen Furchen. Die hohen Wirbel stehen in 1/3 der Lange und sind 5 mm. von der Mittel- linie entfernt. Oberflache mit 30 starken Rippen und scharf markirten Zuwachsstreifen. Hohe 30 mm, Lange 37 mm, Dicke (einer Schale) 18 mm. —Grzybowski, 1899. Remarks.—This variety is the most common form in the Variegated beds. It is usually a smaller, more solid shell with a rounded ventral margin usually not parallel to the hinge-line. The valves are more evenly convex lacking the prominent ante- rior hump so characteristic of toroensis. Grzybowski’s figure shows a shell with the beaks only slightly anterior of the middle of the valves, measuring 37 millimeters in length. It was collected probably from the Variegated beds at Grau although listed with species from the Cardalitos shales of Mal Paso. Length, 31 mm.; height, 27 mm.; semidiameter, 14 mm. Length, 38 mm.; height, 31 mm.; semidiameter, 17 mm. Locality and Geologic Occurrence.—Lower Zorritos of Que. Hiqueron, Punta Picos. Grau (Grzybowsk1). Arca (Senilia) zorritosensis Woods Scapharca zorritosensis Woods, 1922, Bosworth, Geology of North- West Peru, p. 112, pl. 18, figs. 5a-c. Original description—Shell of large or moderate size, inequilateral, inflated, rhomboidal, flattened posteriorly. Anterior margin slightly convex; ventral margin slightly curved, Umbones broad, fairly prominent, with a small anterior curvature. Area large, with numerous ligament-grooves. Hinge-line long, with numerous small transverse teeth. Shell ornamented with stronge ribs tending to become nodular, separated by broad grooves. —Woods, 1922, Remarks.—There are no specimens of this species in our col- lection. According to Woods’ figure, this species seems closely related to Arca dolaticosta Pilsbry and Johnson” from Chiriqui Panama. In gorritosensis, the ribs appear to be more numerous, wider and separated by narrow grooves. The exact geologic horizon of gorritosensis is not known. Locahty and Geologic Occurrence.—Zorritos. 72Pilsbry and Johnson, 1917, Proc. Acad. Nat. Sci. Phila., vol. 69, p. 188., Pilsbry, 1922, Proc. Acad. Nat. Sci. Phila., vol. 73, p. 406, pl. 41, figs. 5, 6. 75 ' OLSSON: PERUVIAN MIOCENE 75 Arca (Senilia) garitensis, n. sp. Plate 1, fig. 1 Shell rather large, solid, with high, wide umbos and sharply contracted posterior submargins ; length and height nearly equal ; ribs about 24, there being about 6 on the posterior submargins ; the ribs are nearly equal in size except near the anterior and posterior margins where they rapidly grow smaller and disap- pear; the ribs are coarsely wrinkled by the growth-lines ; inter- spaces of the same width as the ribs; hinge-area rather high with curved but not approximate beaks; hinge teeth and interior unknown. Length, 78.00 mm. ; height, 80.00 mm. ; semidiameter, 40.00 mm. Remarks.—This species is quite common in the Tumbez sand- stones along the ridge of La Garita but most specimens are thick- ly encrusted with rock. It differs from the other known species of Senilia by its form, the shell being high with wide umbos and sharply contracted posterior slope. Locality and Geologic Occurrence-—Tumbez formation, La Garita. Arca (Senilia) larkinii Nelson Plate 2, figs. 1, 4, 5 Area Larkinti Nelson, 1870, Trans. Conn. Acad. Sei., vol. 2, p. 204, pl. Op We, By Os Wh Arca (Scapharca ?) larkinii Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 111, pl. 5, figs. 16-18. Not Arca Larkinii Grzybowski, 1899, Neues Jahrb, f. Min. ete., Beil. Bd,, 12, p. 633. Original description.—Shell thick and heavy. Anterior extremity short and rounded; posterior more or less produced, Beaks widely separated, raised and very prominent. Ligament area large, about half as broad as long. Surface marked by from 30 to 33 radiating ribs, which are rounded and broader than the spaces between them. Ribs ornamented by rounded tubercles and crossed by numerous fine lines of growth. Teeth numerous, strong, nearly straight, equidistant, except at the extremities of the hinge line, where they become divergent and much stronger. The margin of the shell is deeply scalloped by the extremities of the exterior ribs and grooves. Just above the marginal teeth the inner surface of the shell is markd by fine radiating lines, from one-fourth to one-half of an inch in length. Anterior muscular scar almost circular; posterior elongated and narrow. Length 27.4 millim.; breadth 29.6 millim.; height 25.6 millim.; between umbos 5.8 millim.—Nelson, 1870, Shell medium to large, solid; umbones rather wide with small, slightly coiled and nearly central beaks; umbonal ridge angular with a contracted, flattened to impressed, posterior-dorsal slope ; the anterior side is short and rounded; the dorsal and ventral 76 BULLETIN 68 ; 76 margin is straight and parallel; the posterior margin, obliquely subtruncate, straight, meeting the ventral side usually at an angle of about 80 degrees; both valves similarly sculptured; ribs on the left valve number 33 to 34, there being usually 21 to 22 ante- rior of the umbonal angle and 12 on the posterior-dorsal slope; the ribs in the middle and anterior submargins are strong and separated simply by grooves except on the anterior submargins where the interspaces become wider; the ribs are regularly but not strongly noded by low tubercles which on weathering become hollow or pustulated; the ribs on the posterior-dorsal slope are smaller, smooth or less regularly noded; ribs of the right valve are similar to those of the left but usually with wider interspaces ; cardinal area high, limited by a marginal groove, often smooth or with one or more, irregular, disconnected grooves near the hinge margin; hinge teeth almost continuous, there being usually about Ig 1n the posterior set and 22 in the anterior. Length, 67 mm.; height, 54 mm.; semidiameter, 26.50 mm. Length, 54 mm.; height, 45 mm.; diameter, 45 mm. Length, 77 mm.; height, 71 mm.; diameter, 34 mm. Remarks.—Arca larkinu is very common in the Tucillal beds being one of the most characteristic species of this horizon and as yet has not been found at any other locality. Nelson’s type redescribed and figured by Spieker is an immature form having a length of only 27.5 millimeters. The average size of our speci- mens is about 55 millimeters in length with one shell reaching 77 millimeters. Grzybowski’s records of larkiniw probably refer to chiriquiensis toroensis Spieker. Arca larkinu is clearly a Senilia but differing from most species of that group by its more regular form and smaller, finely sculp- tured ribs. Young specimens of Arca grandis may resemble larkinu in shape but the ribs are higher with deeply grooved interspaces. Locality and Geologic Occurrence-—Tumbez formation, Que. Tucillal at Zorritos. Subgenus NOETIA Gray Area (Noetia) retractata Hanna and Israelsky Plate 4, figs. 2, 8 Arca (Noétia) modesta Grzybowski, 1899, Neues Jahrb. f. Min. ete., Beil. Bd., 12, p. 635, pl, 18, fig. 4. (not modesta Weinckel 1863). Arca retractata Hanna and Israelsky, 1925, Proe, Calif, Acad. Sei., 4th series, vol. 14, p. 61. Original description.—Es liegen mir zwei unvollkommene Exemplare vor, 77 OLSSON: PERUVIAN MIOCENE 77 die aber doch in ihren Haupttheilen erhalten sind. Die Art ist viel kleiner als die vorher genannte, sie diirfte in Grosse der lebenden A. reversa ent- sprechen, zeigt auch in Allgemeinen denselben Bau, doch ist der Schlossrand vorne stark gebogen, so dass die Lunula erhaben ist und der vorne dureb den Kiel abgentrennte Theil coneay erscheint. Oberfliiche mit tiber 30 ziem- lich breiten, aber flachen Rippen verziert. Hohe, 30 mm.; Linge, 30 mm.; Dicke (einer Klappe), 15 mm.—Grzybowski, 1899. Shell of medium size and like A. reversa in general charact- ers; in retractata, the posterior side is usually longer with a straighter and longer hinge-line; the posterior side on reversa is strongly flattened, sharply truncate so that the posterior extermi- ty forms almost a right angle with the ventral margin while in retractata it is impressed and distinctly concave usually meeting the ventral margin at an acute angle; the umbones in retractata are narrower and higher with more central beaks; ribs are low and flat, the interspaces as in reversa beautifully cross-etched by the growth-lines and with an interstitial thread in the interspaces on the umbonal ridge and on the posterior slope. Dimensions of an average specimen: Length, 40.50 mm.; height, 34.00 mm.; diameter, 33 mm. Remarks.—The figure given by Grzybowski of this species is not the common form, the umbonal ridge being more strongly recurved with a resulting more deeply excavated posterior-dorsal slope than usual. Most specimens have the form represented by figure 8 but considerable variation occurs between elongate shells approaching cholana of Spieker on one hand, to high, com- pressed types on the other. Some specimens like figure 2 are quite close to recent reversa. Arca MacDonald Dall** from the Miocene of Costa Rica and Colombia is very closely related to retractata and it is doubtful that the Peruvian shell can be held distinct. A. mac- donaldi has usually a more pointed and produced posterior ex- tremity but this character is not constant, the species being very variable. Dall’s figure of the holotype of macdonaldi, published several years after its original description, is similar to figure 2 of a Zorritos specimen. Locality and Geologic Occurrence.——Lower Zorritos of Que. Zapotal. Que. La Cruz. Upper Zorritos, Zorritos, Que. Picos. Area (Noetia) reversa Sowerby — subsp. Plate 3, figs. 1 Very similar to typical reversa in shape but much larger 73Dall, 1912, Smith, Mise. Coll., vol. 59, No. 2, p. 9., Dall, 1925, Proce. U. S. Nat. Mus., vol. 66, p. 5, pl. 17, fig. 9. Olsson, 1922, Bulls. Amer. Pal., vol. 9, p. 366, pl. 25, figs. 4-7. 78 BULLETIN 68 78 reaching a length of about 80 millimeters or more; umbonal ridge strongly angled with the posterior-dorsal submargins sharp- ly truncate, flattened or weakly arched in the middle; ribs like those of reversa are low, flattened, and separated by narrow in- terspaces which carry an interstitial thread or riblet on the an- terior submargins. Length, 80.00 mm.; height, 71.00 mm.; diameter, 67.00 mm. Length, 83.00 mm.; height, 69.00 mm.; diameter, 71.00 mm. Remarks.—Our collection from Tucillal has two large Noétia which are very similar to recent Arca reversa in all visible char- acters except size. The largest specimen or recent reversa which I have seen, has a length of about 45 millimeters while the Tucillal form is nearly twice this size. Arca reversa is common along the beaches of Ecuador and northern Peru with its south- ern limit at Punta Picos. It is a common fossil in the Pleistocene tablazos. Grzybowski has figured Arca reversa from the Man- cora tablazo beds at Paita. Locality and Geologic Occurrence.-—Yumbez formation, mouth of Que. Tucillal at Zorritos. Superfamily OSTRACEA Family OSTREIDAE Genus OSTREA Linné Subgenus OSTREA s. s. Ostrea latiareata Grzybowski ; Ostrea latiareata Grzybowski, 1899, Neues Jahrb. f. Min., ete,, Beil. Bd. 12, p. 630, pl. 17, fig. 6. 3 Original ddscription.—Schale rundlich, mit breiter, stumpf dreieckiger Area, in deren Mitte eine breite, deutlich langsgestreifte Bandfurche sich befindet. Die Schale ist sehr dick, deutlich lamellos, mit seichter Wolbung. An der Oberfliche verlaufen feine, dichtgedrangte Radialfalten, die beson- ders in der Nihe des Wirbels deutlich hervortreten, sonst von Zuwachsstrei- fen verdeckt werden. Der grosse Muskeleindruck liegt in der Mitte. Hohe 120 mm,; Breite 88 mm.; Breite der Area 58 mm.—Grzybowski, 1899. Remarks.—Oysters are locally common at Zorritos but they are usually too poorly preserved to be determinable. Oyster banks occur in the lower Cardalitos shales and in the Tumbez formation. Two species of oysters were described by Grzybowski from Zorritos. QO. latiareata is a large, coarse species with high, tri- 79 OLSSON: PERUVIAN Mi1ocENE 79 gonal cardinal area and deep ligament socket. The length of the fragmentary specimen figured by Grzybowski is 120 milli- meters. Although I have no specimens, it is probably the com- mon oyster of the Zorritos region. O. sculpta Grzybowski (op. cit., p. 631, pl. 17, figs. 8, 8a) may prove to be an Anomia. Its hinge- line as figured by Grzy- bowski is irregular, anomoid with no clearly defined ligament groove. The exterior is flat, with faint radials. The muscular impression is however, like that of an oyster. Locality and Geologic Occurrence.—Cardalitos formation, Caleto Grau. (Grzybowsk1). Section LOPHA Bolten Ostrea (Lopha) haitensis Sowerby Plate 3, fig. 3 O'strea Haitensis Sowerby, 1850, Quart. Jour. Geol. Soc. London, vol. 6, p. 53. Ostrea Haytensis Gabb, 1873, Trans. Amer, Phil, Soc., vol. 15, p. 257. Astrea haitensis Guppy, 1876, Quart. Jour. Geol. Soc. London, vol. 32, p- 532. Ostrea haitensis Dall, 1898, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, p. 685; pt. 6, p. 156. Ostrea haitensis Maury, 1917, Bulls. Amer. Pal., vol, 5, p. 346, pl. 31, figs. 1, 2. Ostrea haitensis Cooke, 1919, Carnegie Inst., Publ. No. 291, p. 129, pl. d, ie, 1s PA oll te), aie Al Ostrea haitensis Maury, 1925, Bulls. Amer. Pal,, vol. 10, p. 230, pl. 9, figs, 1, 2, Original description.—Testa oblonga, crassa, plicata, plicis paucis (senis ad septenis), magnis, undulatis, subsquamosis, squamis nonnunquam subtu- bulosis; limbo interno omino glabro. This species appears to be related to O. imbricata Lam.; it differs how- ever, in its general form, which is oblong and not orbicular, and in the num- ber of external radiating folds, which are only six or seven in our shell.— Sowerby, 1850. Remarks.—The Peruvian examples of this oyster are frag- mentary but there is little doubt of their correct identification with haitensis of the West Indian and Caribbean Miocene. The best specimen here figured, is a part of the left or sessile valve. It shows the deep, central depression usually seen on left valves of typical haitensis and strong, folded, subspinous ribs. This type of sculpture is quite similar to Colombian specimens of haitensis in our collection except that in the Peruvian form, the ribs are more strongly folded. I do not know vespertina Conrad and veatchii Gabb of the Californian Miocene which some authorities consider as equiva- lent to haitensis or but subspecifically distinct. Arnold’s*™* fig- 74Arnold, 1909, Bull. 396, U. S. Geol. Survey, p. 77, pl. 24, figs. 4, 5 80 BULLETIN 68 80 ure of vespertina and Stewart’s’™ figure of the holotype of veatchi do not closely resemble typical haitensis. As Arnold pointed out, Ostrea vespertina is smaller, relatively much nar- rower, and usually more falcate in outlines and carries plaits more regular in size and generally fewer in number than haiten-" sis. The figures of vespertina bear considerable resemblance to Ostrea sculpturata Conrad from the Upper Chesapeake Miocene and Pliocene of the Atlantic States, a resemblance already in- dicated by Arnold. On the other hand, the figure given by White of veatchi looks like a good haitensis. As Woodring has indicated, the small oysters figured by Joukowsky™ as haiten- sis from Garachiné, Panama, probably belong to the group of Ostrea megodon Hanley. j Locality and Geologic Occurrence.—Montera formation, Bay- ovar and Que. Montera. : Superfamily PECTINACEA Family PECTINIDAE Genus PECTEN Muller Subgenus PECTEN, s. s. Pecten (Pecten) illesca, n. sp. Plate 4, figs. 4,6,7,12; Plate 5, fig. 7 Shell small, inequivalve, strongly sculptured; the right valve is strongly convex, its greatest inflation being in the center while the left valve is flattened, somewhat arched in the lower or ven- tral portion; in the right valve, the sculpture consists of high, square ribs which number about 18, the largest in the middle and smaller towards the sides; the interspaces are deep, of the same width as the ribs; in the left valve, the ribs number about 17 and are narrower, somewhat lower with wider interspaces ; both valves show a fine, secondary sculpture which is best de- veloped on the left valve; in the left valve, this consists of a fine ridge or thread on the sides of each rib and a peculiarly frim- briated cross-threading in the interspaces; this submiscroscopic sculpturing is much finer on the ventral part of the valves; in the right valve, the ribs are not bordered by the secondary rib or thread but the submicroscopic sculpture seems the same; ears 75Stewart, 1930, Acad. Nat. Sci. Phila., Special Publication, No. 3, p. 128, pl. 14, fig. 4. 76White, C. A., 1884, 4th Annual Report. U. S. Geol. Survey, p. 316, pl. 72, fig. 1 77Joukowsky, 1906, Mém. 35, Soc. Phys. Genéve, p. 170, pl. 6, figs. 20, 21, Ps, GB}, BVA, BR, BYE, BS 81 OLSSON: PERUVIAN MrIocENE 81 very small, especially in the right valve; hinge crura strong. Length, 19.25 mm.; height, 19 mm.; semidiameter, 7 mm. ; (right valve. Length, 19 mm.; height, 18 mm.; semidiameter, 2 mm. (left valve). Remarks.—This small! species is locally very common in the Sechura Miocene. It appears to be a true Pecten, the right valve being very convex while the left valve is nearly flat or simply arched in the ventral region during its mature or gerontic stages. The ears are extremely small in the right valve, somewhat larger and subequal in the left. In addition to the strong ribs there is a delicate, submicroscopic sculpture best seen in the interspaces of the left valve. In the Séchura collection, there is an imperfect left valve and numerous fragments of a species akin to Pecten gatunensis Toula, from Panama. The ribs seem to widen out more rapidly on the Peruvian shell but the material is too fragmentary for close comparison. Locality and Geologic Occurrence.—Montera formation, Zone A, Que. Montera. Subgenus CHLAMYS Bolten Section PLAGIOCTENIUM Dall Pecten (Plagioctenium) woodringi Spieker Plate 5, figs. 2, 5 Pecten, sp. ind. Nelson, 1870, Trans. Conn. Aead., vol. 2, p. 205. (in part). Pecten woodringi, Spieker, 1870, Johns Hopkins University, Studies in Geology, No. 3, p. 125, pl. 7, figs. 4, 5. Original description.—Shell small. slightly inequivalve, the left valve more convex, subequilateral. The right valve somewhat flattened, with about 15 round ribs, arranged in fan shape, a little wider than the interspaces. Submargins steep, smooth, flat; anterior ear with four distinct radiating ribs, crossed by sharp concentrically channelled threads which extend across the part next the submargin in reversed curves, making the complete thread- ing S-shaped; byssal noteh prominent; comparative length of ear not known. Posterior ear subrectangular, with sculpture of very fine, closely spaced concentric threads and very faint radial ribs. Sculpture on the dise of very fine growth-lines which cross the ribs and interspaces in smooth eireles. Inner shell fluted. The left valve similar to the right; anterior ear ornamented by about six somewhat widely spaced radiating ribs which are crossed by fine lines of growth; outline unknown. Posterior ear unknown excepting a fragment near the submargin, which shows several radiating ribs crossed by very fine lines of growth. Sculpture on dise of fine growth-lines which eurve upward on the ribs and downward on the interspaces giving the threading a sinu- ous aspect. Both valves have apical angles of 90° or more. The margins form approximate semicircles. Dimensions: Right valve, length, 37.5; height, 36.25 mm.; left valve, length, 32; height, 30.75 mm,—Spieker, 1922. Remarks.—The types of Pecten woodringi from _ the Yale collection are refigured as the restored outlines of the left 82 BULLETIN 68 82 valve in Spieker’s figure is misleading. In Spieker’s figure 5, the anterior ear is shown as large and greatly produced while actually the anterior ear is probably a little smaller than the posterior as in recent tumbezensis d’Orbigny. In figure 4, the anterior ear of the right valve is also too long. Pecten woodringi is related to Pecten tumbezensis dOrbigny of the West Coast, differing from the recent shell principally by its more numerous and narrower ribs. In tumbezensis, there are usually 14 ribs in the right valve while woodringi has 16. The left valve of tuwmbezensis has 15 ribs while woodringi has 17. The sculpture of the ears of the two species is quite simi- lar, the anterior ear being strongly ribbed while the left is nearly smooth. Spieker records woodringi from several localities in the Upper Zorritos but I have seen no authentic specimens other than those in the Nelson collection at Yale. The matrix on these specimen indicate that they are from the Tucillal horizon. Locality and Geologic Occurrence.—Tumbez formation, prob- ably Que. Tucillal, Zorritos (Nelson). Pecten (Plagioctenium) nelsoni, n. sp. Plate 5, figs. 3, 6 Shell of medium size, thin, nearly equivalve and only slight- ly convex; right valve with about 16, low, rounded to triangu- lar-shaped ribs separated by flattened interspaces; the ribs and interspaces are clearly separated and distinct on the nepionic portion of the valves but on the ventral portion, the ribs become lower, flatter, their sides merging gradually into the interspaces ; on the left valve the ribs are similar but narrower and with wides interspaces. The nepionic half of the valve is smooth while the lower half is covered with fine, even, crowded, raised concentric threads; ears typical and probably subequal in size, only the right posterior and the left anterior preserved in our specimens; the right posterior is flattened with two, thread-like radials and fine growth-lines; the left, anterior ear similar but with a wide, shallow notch opposite the deep byssal notch of the right valve and ornamented with five, irregularly spaced, radial threads and fine, concentric threadlets; interior of shell fluted in harmony with the external ribs. 83 OLsson: PERUVIAN MIOCENE 83 Height, 41 mm.; breadth, 44 mm.; semidiameter, 5 mm. (right valve). Remarks.—This species resembles Pecten coderensis Harris from Venezuela. In coderensis, the ribs are flatter and the sur- face of the shell is nearly smooth, the concentric growth-lines being very faint. In nelsoni however, the nepionic or upper part of the valves have a smooth sculpture changing sharply to one of coarse raised, concentric threads on the lower half. Locality and Geologic Occurrence-—Tumbez formation, Que. Tucillal. Section LYROPECTEN Conrad Pecten (Lyropecten) hopkinsi, n. sp. Plate 5, figs. 1, 4 Shell large or medium size, little convex, subequivalve; the right valve with about 15 ribs; these are rectangular in section, flat-topped and separated by flat interspaces of the same width as the ribs; the ribs at first are simple or plain, later carrying a medial line or groove so that they appear weakly divided; a line on each side of the middle one appears shortly further subdi- viding the main rib into four parts; the interspaces are flat and nearly smooth but are feebly lined near the ventral margin; pars unequal, the anterior one carrying a deep byssal notch, its upper face with 5 or 6, strong ribs crossed by scabrous concen- tric threads; posterior ear with 12 or more fine riblets; the left valve similar to the right but with the ribs somewhat more round- ed; both ribs and interspaces are more strongly sculptured by the radial threads so that they are more cord-like in appearance ; interior unknown. Length, ?; height, 50.00 mm. Length, 67.00 mm.; height, 64.00 mm. ; semidiameter, 6.00 mm. Remarks.—Fragments of this large species are quite common at Tucillal but perfect specimens have not been obtained. It is a typical Lyropecten easily distinguished by its large size and sculpture from the other Miocene species of northern Peru. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Superfamily ANOMIACEA Family ANOMIIDAE Genus ANOMIA Linné Anomia berryi Spieker Plate 3, figs. 2, 6 Anomia berryi Spieker, 1922, John Hopkins University, Studies in Ge- ology, No. 3, p. 127, pl. 7, figs, 6, 7. 78Harris, 1927, In Hodson, Bull, Amer. Pal., vol. 18, p. 34, pl. 18, figs. 2, 4, 5 84 BULLETIN 68 84 Original description.Shell large, heavy. very convex, fairly regular. Left valve much inflated. Umbones usually broad, somewhat incurved. Sculpture of radial ribs, somewhat irregular, between the major ones of which are from three to five minor ribs which are seen under a lens to be crossed by fine, wavy growth-lines, with the formation of something like nodes. The irregular, wavy concentric growth-lines are fine from the hinge half-way down the shell; on the ventral half they are coarse and imbricate. Interior of valves not known. Length 60; height 46.5; diameter of left valve, 26 mm.—Spieker, 1922. Remarks—As common to this genus of sedentary mollusks, this species exhibits considerable variation in size, convexity and shape. The lower or byssal valve has not been seen but the up- ‘per or free valve is often very common. In its most common and typical form, the upper valve is strong ly convex as figured by Spieker and shown in our figures. The opposite extremes are nearly flat or irregularly-shaped valves as illustrated by figure 6. The sculpture is typically fine but certain of the radials are usually enlarged and riblike in form but ap- parently never as strong as in Anomia gabbi Pilsbry and Johnson from Santo Domingo. The interior has not been seen The Ostrea sculpta, described by Grzybowski” from Grau, ac- cording to its figure, has the narrow, irregular-shaped hinge-line of Anomia but the impression of its adductor muscle is ostroid. Locality and Geologic Occurrence.—Variegated beds, Punta Picos, Que. Heath, etc. Montera formation, Que. Montera, Se- chura. ORDER TELEODESMACEA Superfamily ASTARTACEA Family CRASSATELLIDAE Gray Genus EUCRASSATELLA Iredale Subgenus HYBOLOPHUS Stewart It is uncertain how great systematic value can be attributed to the opisthogyrate beaks and umbones of Crassatella gibbosa Sowerby and the basis of Stewart’s subgenus Hybolophus. This character, principally a posterior twist of the umbones so that the flattened beaks have a posterior inclination is displayed to a variable degree on many species of the gibbosa group. It is best developed on such forms as gibbosa which are quite convex with a strongly contracted, excavated posterior-dorsal side. It is very evident in FE. berryi Spieker (see Plate 6, figs. 3, 8), of the Lower Zorritos. It is frequently seen on specimens of E. trint- “’Grzybowski, 1899, Neues Jahrb. Beil. Bd. vol. 12, p. 631, pl. 17, figs. 8, 8a 85 OLSSON: PERUVIAN MiIocENE 85 taria Maury var. venezuelana Hodson from the Miocene of Colombia and Venezuela while other shells do not show this fea- ture at all. &. nelsoni Grzybowski from the Cardalitos shales seldom shows this character to a notable degree although Grzy- bowski’s figure 2 on his Plate 19 shows a slight posterior inclina- tion of the beaks. F. aviaguwensis Hodson and its West Coast variety may show this character to a slight degree. These spe- cies are so closely related to gibbosa that a common genetic origin is indicated and consequently belong to the same group. The most highly specialized members such as EF. berryi and gibbosa have the strongest posterior twist showing that it is prin- cipally a phylogerontic character. If Hybolophus be admit- ted principally on phylogenetic grounds, the subgenus may be recognized for the American West Coast and Miocene Eucrassa- tella whose relations lie with E. gibbosa Sowerby, the group dat- ing back to late or possibly mid-Oligocene times. Eucrassatella (Hybolophus) berryi Spieker Plate 6, figs. 3, 8 Crassatellites (Scambula) berryi Spieker, 1922, Johns Hopkins Univer- sity, Studies in Geology, No. 3, p. 131, pl. 7, figs. 9, 10. Original description.—Shell of medium size, anteriorly inflated, posterior- ly attenuate. Anterior margin rounded; ventral margin rounded anteriorly, ascending posteriorly in a reflex curve to the apex of the first of two mar- ginal angles, The posterior dorsal margin is about straight, descending to meet the apex of the second posterior marginal angle. Umbones high, erect, inflated, prosogyrate, proximate, the top flattened, with the flat sur- face sloping backward, Anterior surface convex. A prominent keel, sharp on and near the beaks and flattened ventrally, runs from the umbo to the lower marginal angle; before the keel there is a sulcus, narrow and sharp umbonally and shallower ventrally. Behind the posterior half of the keel is a flat to concave surface which is often bounded posteriorly by a second vestigial keel. Seulpture of strong concentric undulations, their dorsal slopes steeper, sharp on the beaks and decreasing in prominence ventrally but evident over all of the shell, sharper anteriorly on the median surface. There is additional sculpture of fine growth-lines. The concentric sculpture parallels the margins. Lunule deeply impressed, distinct, oval; escutcheon of similar lines but more lanceolate. Hinge normal. Muscle sears deeply impressed; internal valve-margins smooth; parallel line (palial line) sharp. Length, 40.5; height, 28; diameter, 20.5 mm.—Spieker, 1922. Remarks.—tThis distinct species is apparently restricted to Lower Zorritos horizons where however it is very common. It is always smaller than nelsoni, our largest specimen which is not quite perfect measures about 43 millimeters in length. The valves are strongly convex on the anterior half, becoming depressed on the posterior side of the middle. The umbos are full, inflated, the narrowly flattened beaks having a definite posterior inclina- 86 BULLETIN 68 86 tion. The escutcheon is quite narrow and not deeply impressed. The surface sculpture consists of strong, regular concentric ribs or narrow undulations which may be strong over the whole sur- face or fade out on the center of the disk and near the ventral margins. The posterior area is smooth, bounded by a strong keel and usually with a faint or vestigial medial cord. Anderson®® has recorded this species from Zone R, Tubara village in northern Colombia but I strongly suspect that Ander- son’s specimens belong to E. trinitaria venezuelana Hodson which is the common Crassatella of the Tubara beds. Locality and Geologic Occurrence.—Lower Zorritos of Zapo- tal (type locality), Que La Cruz, Que. Hiqueron. Eucrassatella aviaguensis peruviana, n. subsp. Plate 6, fig. 2 Shell of medium size to large, solid, inflated; beaks at the an- terior one-third, the anterior side regularly rounded, the poster- ior, longer, produced and more or less pointed at its end; the posterior-dorsal margin slightly concave, excavated with a weak, but distinct, umbonal cord-like ridge between which and the margin there is a second, vestigial rib; the valves have their maximum convexity in the zone extending from the beaks to the ventral margin; there is a slight but wide sinus just below the umbonal slope so that when the valves are viewed from above, they appear distinctly contracted in the posterior region; the beaks are flattened, often with a slight posterior inclination, and sculptured with strong, concentric undulations which cover a belt about 9 millimeters wide measured from the beak, then fading rapidly away; the surface of the valves is smooth in the middle, strongly sculptured with subregular growth-lines on the anterior submargins; lunule deep, cordate, limited by a sharp rim; escutcheon elongate-elliptical. Length, 42 mm.; height, 31 mm.; diameter, 24.5 mm. Length 45 mm.; (imperfect) ; height, 43 mm.; semidiameter 14.5 mm. Length, 62, mm.; height, 50 mm. ; semidiameter, 15 mm. Remarks.—Our shells from the Lower Miocene of Ecuador and Sechura, are so close to aviaguensis F. Hodson®! from Vene- zuela that they can be considered no more than a subspecies. The main difference lies in the shape of the lunule which in avia- guensis is deeper, more elliptical and limited by a sharper rim. 80Anderson, 1929, Proc. Calif. Acad. Sci., 4th series, vol. 18, p. 159 81F. Hodson, 1927, Bulls. Amer. Pal., vol. 13, p. 45, pl. 28, figs. 4, 7, 8, 10 87 OLsson: PERUVIAN M10cENE 87 Locality and Geologic Occurreice.—Montera formation, Zone A. Bayovar, Sechura. Miocene sandstones in railroad cuts aboui halfway between Amen and Playas, Ecuador. Eucrassatella (Hybolophus) nelsoni Grzybowski Plate 6, figs. 1, 4 Venus nelsoni Grzybowski, 1899, Neues Jahrb,, Beil. Bd. vol. 12, p. 639, pl, 19, figs. 2, 2a. Crassatellites (Scambula) nelsoni Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology No, 3, p. 128, pl. 7, fig. 8. Crassatellites charanensis Woods, 1928, Bosworth, Geology of NW Peru, p. 112, pl. 20, figs. 1, 2, 3. Crassatellites pizarrot Hanna and Israelsky, 1925, Proce. Calif. Acad. Sci., 4th series, vol. 14, No. 2, p. 46, pl. 7, fig. 1. Shell is of moderate size to large, moderateiy convex, solid; anterior side wide and well-rounded, the posterior side varying from short cuneate to rather long, produced Lut not ending in as sharp a point as in the recent gibbosa or as in the members of the trimitaria group of the Caribbean Miocene; umbos strongly _ flattened and sculptured with strong concentric undulations ; an- terior submargins usually sculptured with fine, regular concen- tric riblets fading away on the rest of the shell; lunule deep, excavated; escutcheon deep, narrow, elliptical; umbonal ridge low, rounded and scarsely defined. Remarks.—Eucrassatella nelsoni is a common and character- istic species of the Cardalitos shales and in the Zorritos region has not been certainly recognized at any other horizon. The typical shell described by Grzybowski as Venus nelsoni from Grau or Mal Paso is a comparatively short, high, sub-trigonal shell with nearly central beaks, a broadly rounded anterior side and moderately produced posterior extremity. Woods probab- ly not recognizing that Grzybowski’s Venus nelsoni was actually a Crassatella, redescribed the shell from Quebrada Charan as charanensis and pointed out its affinities with C. kingicoloides Pritchard from the Miocene of Victoria. C. pizarroi Hanna and Israelsky from the Cardalitos shales of upper Quebrada Heath must also be considered a direct synonym of this species. Commonly associated with typical nelsoni, are more elongate forms with a longer, produced and pointed posterior extremity and shorter anterior side. These shells resemble the group of E. trimtaria Maury from the Caribbean Miocene but may be dis- tinguished in that the dorsal-posterior region is straighter and not deeply curved or excavated, the posterior extremity is less 88 BULLETIN 68 88 pointed as well as possessing a lower, more smoothly rounded umbonal slope. Locality and Geologic Occurrence.—Cardalitos formation, Mal Paso, Upper Quebrada Heath, Quebrada Charan. Eucrassatella (Hybolophus) gibbosa tucilla n, subsp. Plate 6, fig. 6 Crassatella gibbosa Nelson, 1870, Trans. Conn, Acad., vol. 2, p. 2038, pl. 7, fig. 9. (not Sowerby). Shell large, slightly to moderately convex, solid; beaks a short distance anterior of the middle; anterior side straight, descend- ing in the lunular region, then smoothly rounded at the end; the ventral side is broadly and evenly rounded, often slightly impressed in the posterior portion; posterior-dorsal side straight to slightly curved and strongly descending; usually a weak, bi- carinate umbonal ridge; shell is slightly but broadly convex across the middle and usually with a wide, depressed zone be- tween the middle and the umbonal ridge; surface smooth except for growth-lines; lunule and escutcheon elliptical and deeply impressed; umbones with flattened beaks, normal or becoming slightly opisthogyrate. Length, imperfect 65 mm.; height, 53 mm.; semidiameter, 18 mm. Length, 70 mm.; height, 52, mm.; diameter, 37.5 mm. Remarks.—-This form is closely related to gibbosa Sowerby of the recent Panamic fauna and Nelson referred his specimens without question to the recent species. Spieker who restudied the Nelson collection considered some specimens as true gibbosa and other as nelsoni. Our examples from Tucillal are all frag- mentary but belong to a single form, similar to Nelson’s figure but easily distinguished from both nelsoni and gibbosa. They seem to represent an intermediate form between the two species. From nelsoni, they differ by their larger size, smooth, anterior submargins and slightly opisthogyrate beaks. They differ from gibbosa in being larger, less convex, less pointed posterior ex- tremity and straighter, less contracted posterior-dorsal submar- gins. The umbones are slightly opisthogyrate and it is mainly on this character that the shell is here associated with gibbosa rather than as a variety of nelsomi. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal Zorritos. 89 OLSSON: PERUVIAN MI0cENE 89 Superfamily LUCINACEA Family LUCINIDAE Genus LUCINA Bruguiére Subgenus HERE Gabb Lucina (Here) iduna, n. sp. Plate 7, fig. 1, Plate 8, figs. 2, 5, 6 Shell small, plump, solid, equivalve; the valves are subcircu- lar in form, strongly convex, inequilateral, with the beaks near the anterior one-fourth; umbones quite prominent, passing into the adjacent, prosogyrate beaks; the external sculpture of the valves is divided into 3 prominent areas by 2 deep, radiating grooves which extend from the beaks to the ventral margin; the first of these defines the posterior area, the second extends along the anterior side; the central area which lies between these grooves is broad and fan-like, the other 2 are lower and narrow; the whole surface is overrun by coarse growth-lines which are divided by deeper concentric lines marking resting stages; an average shell shows 5 or 6 of these resting marks; the lunule is _ large, broadly elliptical, mostly external but the upper end is immersed, forming a deep, pit-like depression which passes be- neath the beaks; hinge with small cardinal teeth and strong la- terals; the outline of the ventral margin usually deeply fur- rowed by the radiating grooves, internally crenulated. Length, 12.50 mm. ; height, 13.00 mm.; diameter, 10.50 mm. Remarks.—As pointed out by Woodring*’, the Atlantic spe- cies placed by Dall under Here are not typical, lacking the deep- ly sunken or immersed lunule of the type species. These East American species were referred by Woodring to Linga de Gre- gorio with Lucina columbella Lamarck from the Aquitanian Miocene as genotype. Lucina columbella does not differ except in specific characters from Lucina pennsylvanica (Linné) which Stewart*® concludes is the true type of Lucina Bruguiére. Thus the name Linga is an objective synonym of Lucina, s. s. The subgenus Here Gabb and its type species Lucina (Here) excavata Carpenter (generally known at L. (H) richthofeni Gabb) has been recently discussed and figured by Stewart**. Excellent figures of this species from a younger shell showing 82Woodring, 1925, Carnegie Inst. Washington, Pub. No. 366, p. 118. 83Stewart, 19380, Acad. Nat. Sci. Philadelphia, Special Publication No. 3, Dette 84Stewart, 1930, op. cit., p. 180, 181, pl. 15, fig. 3, pl. 17, fig. 5. 90 BULLETIN 68 90 both internal and external views have been given by Dall®°. Dall’s figure of the interior of the left valve shows a deeply ex- cavated lunule, partly effacing the anterior right cardinal. The interior of our specimens has been modified through mineraliza- tion so that the hinge teeth are not well preserved. There seem to be two small cardinal teeth in the right valve, the anterior one being very minute. In the left valve, remains of the posterior tooth are evident, but the anterior one seems to be lacking. The lunule is large, broadly elliptical with only a small part im- mediately beneath the beaks being depressed into the hinge plate. On specimens with closed valves, the immersed portion of the lunule shows as a deep, rounded hole, penetrating beneath the small, coiled beaks. The immersed part of the lunule is smaller than figured for excavata but according to Dall, the excavation of the lunule is a variable feature in the recent species. The external sculpture of zduna differs greatly from that of excavata. The dorsal area is well defined by a deep, wide groove forming a broad, rib-like area. A similar, deep groove extends through the anterior portion forming a similar rib-like area in the center of which lies the broadly elliptical lunule. The growth- lines are coarse, divided by deep, resting marks such as seen in Lucina trisulcata Conrad. Dall’s figure of the exterior of ex- cavata (figure 7), show faint, obsolete folds feebly defining the posterior area and on the anterior side extending a short dis- tance from the ventral margin. Lucina prosoptera described by Grzybowski from Grau (Cardalitos shales) is tentatively referred to Here. Grzybowski does not figure the interior or lunule but the strongly differen- tiated dorsal areas show the form to belong to Lucina, s. s. or to this subgenus. . Locality and Geologic Occurrence——Montera formation, Lu- cina zone Que. Montera near Bayovar. Subgenus ILLESCA, n. subg. Type.—Phacoides (Here) andersoni Olsson86 Plate 7, fig. 7 The following is a description of the subgenus Jilesca: Shell small with strong concentric sculpture forming a regu- lar series of rounded rib-like folds: dorsal areas well defined; 85Dall, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 827, pl. 40, figs. 7, 9. 86Olsson, 1930, Bulls. Amer. Pal., vol. 17, p. 24, pl. 2, figs. 5, 6, 7. 91 OLSSON: PERUVIAN MI10cENE 91 lunule small, entirely immersed beneath the beaks, deeply ex- cavating the hinge-plate; hinge of the right valve with a single, large cardinal tooth and two socket-shaped laterals; the left valve has a smaller, narrower cardinal tooth with weaker lateral teeth bounding deep, sockets for the insertion of the right later- als; ventral margin feebly crenulated, often becoming sulcated. Remarks.—lIllesca differs from Here Gabb to which it is ob- viously related in having the sma!l lunule entirely immersed into the hinge-plate and in both valves seems to have completely ef- faced the anterior cardinal. The posterior area is well-defined, depressed and flange-like in appearance. Lucina (Illesca) ander- soni is quite common in the basal Talara formation at Yasila. Phacoides (Here) nonurensis Olsson®’ described from the Upper Eocene of Nonura Bay, Peru should probably be referred to Stewart’s new section Quasilucina®® with Lucina carinifera Conrad, a Claibornian species as genotype. The Holotype of nonurensis which is the only specimen known, has both valves tightly closed so that the hinge and interior are not visible. There is a large lunule which seems entirely external but the portion immediately beneath the beaks is concealed by matrix. The strong, concentric lamellar sculpture somewhat resembles that of Lucian hamatus Dall from Claiborne but the posterior area is less strongly defined. Lucina trictracensis, n. sp. Plate 6, fig. 5; Plate 7, fig. 2 Shell small, lenticular, subcircular, equivalve; dorsal margin somewhat shorter than the greatest length of the shell which is situated near the middle, equidistant from the beaks and ventral margin; anterior, ventral and posterior margins evenly rounded and form part of the same circle; beaks nearly central, adjacent, prosogyrate; dorsal-posterior area undifferentiated, being only slightly depressed with respect to the adjacent surfaces; the lunule is small discrepant, a little larger in the right valve; sur- face sculpture consists of regular and somewhat distantly spaced, concentric raised threads or small lamellae and fine growth-lines ; interior unknown. Length, 21.25 mm.; height, 20.00 mm.; diameter, 9.25 mm. Remarks.—This small Lucina is quite common near Tric Trac 87Olsson, 1930, op. cit., p. 25, pl. 2, fig. 8. 88Stewart, 1930, Acad. Nat. Sci. Philadelphia, Special Publication No. 3, p. 178. 92 BULLETIN 68 92 Point but unfortunately we have no perfect specimens or one en- tirely free from the matrix in which it is imbedded. It is a small lense-shaped species with evenly but not strongly convex valves, undifferentiated posterior areas and a small discrepant lunule. The regular, distantly-spaced, concentric threads or small lamellz are similar to those of Lucina jamaicensis Lamarck (L. alba Link) which Stewart concludes is the type of the sub- genus Anodonta Link and in Dall’s classification of Phacoides. It differs from this group by its undifferentiated dorsal-posterior area. It is also similar to Lucimoma in its. sculpture. In the absence of any knowledge of the hinge and interior, the subge- neric affinities of this species cannot be determined and it is re- ferred to Lucina undifferentiated until such times as these may be found. | Locality and Geologic Occurrence.—Montera formation, -Tric Wire IP, Genus LORIPINUS Monterosato Subgenus PEGOPHYSEMA Stewart Loripinus (Pegophysema) sechura, n. sp. Plate 7, figs. 6, 8 Shell small or medium size, subcircular, moderately to strong- ly convex ; beaks near the anterior one-third, are small, adjacent and slightly coiled; the maximum convexity of the valves is near the middle; posterior-dorsal margin or hinge line straight ; the anterior side a little contracted and depressed, beyond this the anterior, ventral and posterior margins of the valves are nearly circular; lunule small, discrepant being noticeable larger in the right valve; posterior-dorsal area feebly defined, being slightly depressed as in chrysotoma; interior somewhat coarsely pustulate, the pallial line quite close to the margins of the valve; the anterior muscle scar divided into two parts, a smaller an- terior portion and an elongate aiterior portion; margin simple. Length, 35 mm.; height, 30 mm.; diameter, 18.25 mm. Length, AS sania, S InSKeat, BA soar, 9 Charen, uo) wom, ILeneiln, aS image. ¢ height, 34 mm.; diameter, 23 mm. Remarks.—In size and general form sechura is very similar to L. inca Olsson, described from the Chira shales and is possibly a varietal form of that species. On account of their differences in age, and as very close distinctions must generally be drawn in separating the recent species of Loripinus, it is thought best to regard mca and sechura as distinct, at least until the internal 93 OLSSON: PERUVIAN MIocENE 93 characters of inca are known. The material of inca consists of two specimens which do not show the interior or lunular area. In inca, the surface is smoothish, the growth-lines on the mid- dle of the valves being quite faint while the whole surface 1s marked with feeble, somewhat waved, radial striae. In sechura, the growth-lines are coarse, developing a harsh, surface sculpture while the radial striz seem to be lacking. The internal features have been partly preserved on an internal mold of an old shell. The interior of the valve was very coarsely pustulated with the pallial line situated quite close to the ventral margin. The an- terior muscle scar is quite distinct, a smaller anterior portion and a greatly lengthened posterior portion. On the basis of these muscle characters, sechura belongs to Stewart’s subgenus Pegophysema which includes all the known American forms. Locality and Geologic Occurrence.—Montera formation, Que. Montera near Bayovar. ; Genus MILTHA H. and A. Adams Miltha pacifica, n. sp. Plate 7; figs: 3, 45 5 Shell of medium size, subcircular, depressed to slightly con- vex; the outlines of the valves vary from nearly circular to forms which are noticeably higher than long; the posterior-dorsal margin or hinge-plate nearly straight to slightly arched, the small, forward pointing beaks at the anterior one-fourth; an- terior-dorsal side excavated in front of the beaks but no lunule visible on our specimens; posterior area depressed, defined by a change in direction and coarseness of sculpture; the surface of the valves is sculptured with fine, concentric threads, some of which become coarse and raised lamellz on the posterior area. Length, 53 mm.; height, 48 mm.; diameter, 16 mm. (Holo- type) Length, 46 mm.; height, 48 mm.; diameter, 13 mm. Remarks.—This fossil is represented by abundant material but all the specimens are fragmentary or have the surface part- ly encrusted with rock. The hinge is poorly preserved in one right valve, and shows what appear to be remains of cardinal teeth and a wide, ligamental area as in true Miltha. The an- terior adductor is long, narrow, with the pallial line lying below and situated about the same distance from the margin as in chipolana Dall and caloosaénsis Dall. Externally the valves resemble Arnold’s®® figure of Phacoides 89Arnold, 1909, Bull. 396, U. S. Geol. Survey, p. 57, pl. 6, fig. 6. 94 BULLETIN 68 94 (Miltha) sanctaecrucis Arnold from the Miocene of California which Stewart regards as presumably a true Miltha. The pos- terior area in sancte crucis and pacifica is defined principally by being more depressed and in a change in sculpture and not by an impressed line or groove as true in childreni, xantusi or the other typical Milthas. Miltha sanctecrucis is a larger and propor- tionally longer shell. Miltha woodi Olsson from the basal Talara of Yasila as point- ed out in Part 3 of this series, is a true Miltha related to the typical members of that genus. Locality and Geologic Occurrence.—Montera formation, Lu- cina zone, Que. Montera near Bayovar. Genus PSEUDOMILTHA Fischer Subgenus ZORRITA, n. subg. Type.—Pseudomiltha (Zorrita) petersoni, n. sp. The following is a description of the subgenus Zorrita: Shell broadly subovate, with length exceeding the height ; pos- terior-dorsal area depressed and also defined by a marked change in direction of sculpture; hinge edentulous, the ligament partly external; interior often pustulate ; anterior muscle scar elongate, lucinoid. Remarks.—From typical Pseudomiltha, genotype Lucina gi- gantea Deshayes, of the European Eocene, Zorrita is distin- guished by its differentiated posterior-dorsal area which is deep- ly impressed upon the internal molds. True Pseudomuiltha is usually of subcircular form while Zorrita is broadly subovate, some shells being quite elongate. The small subcircular species such as Lucina anodonta Say and Lucina floridana Conrad usu- ally referred to Pseudomiltha are not related to Zorrita. Large specimens of Zorrita from the lower Miocene beds of Ecuador have a length of 120 millimeters thus exceeding Pseudomiltha gigantea in size. Phacoides (Pseudomiltha?) megameris Dall from Jamaica which is probably not a true Pseudomultha is near- ly twice as large and much heavier. Pseudomiltha (Zorrita) petersoni, n. sp. Plate 13, fig. 1 Shell of medium size to large, equivalve, broadly subovate, depressed to slightly convex; umbones inconspicuous with the small, pointed and slightly curved beaks near the anterior one- fourth ; posterior-dorsal or hinge-margin straight ; posterior side 95 OLSSON: PERUVIAN MIocENE 95 straight to little concave, appearing obliquely truncate; anterior and ventral margin usually well rounded; in the more e!ongate forms the ventral margin becoming straighter; the external sculpture consists of rather coarse and irregular concentric growth-lines sometimes with faint, radial striz; the posterior- dorsal area is well differentiated by being flattened to depressed, and by a sharp change in direction of sculpture; this posterior area is deeply impressed upon the internal molds; a small, nar- row area on the anterior submargins is often strongly impressed ; interior more or less pustulated and radially striated near the margin; hinge edentulous without cardinal and lateral teeth ; an- terior muscle scar elongate joining at its lower anterior side with the pallial line. Length, 69 mm.; height, 60 mm.; diameter, 24.5 mm. Length, 85 mm.; height, 73 mm.; diameter, 25 mm. Remarks.—This fossil is common in the Cardalitos shales of Sechurita and in the same beds in upper Quebrada Tucillal but nearly all the specimens found, are internal molds or have the external shell badly altered through a change to gypsum. A few specimens in which the hinge is visible, although somewhat weathered, show the entire absence of cardinal teeth while the lack of any impressions along the hinge margin, prove the ab- sence of the laterals as well. On the internal molds, the pos- terior and dorsal areas are strongly differentiated, being strong- ly depressed to excavated and defined by a bounding angle which passes through or along the lower side of the posterior adductor scar. The average size of the species is 60 to 70 millimeters but large shells may reach 85 millimeters in length. The lunule was very small or absent. I take pleasure in naming this interesting shell for Dr. G. Peterson, Geologist and Manager of the Zorritos Oil Fields in appreciation of his interest and codperation during my repeated visits to the Zorritos region. Locality and Geologic Occurrence —Cardalitos formation, Se- churita: headwaters of Que. Tucillal. Pseudomiltha (Zorrita) petersoni aquada, n. subsp. Plate 13, fig. 4 Shell large, broadly ovate, flattened to slightly convex; beaks small, situated at the anterior one-third with flattened, incon- spicuous umbones; posterior-dorsal areas deeply impressed, 96 BULLETIN 68 96 marked off from the rest of the surface by a pronounced angled umbonal slope and by a sharp change in sculpture; surface sculpture consists of coarse lines of growth; there are also fine, radial lines on the posterior-dorsal area producing a faintly retic- ulate sculpture ; the shell was probably thin as the lines of growth and faint pustules on the interior of the shell, are seen together ; a deeply impressed line or groove is often seen extending from the beaks along the anterior side. Length, 103 mm.; height, 86 mm.; semidiameter, 9 mm. Length, roo mm.; height, 81 mm.; semidiameter, 6.5 mm. Remarks.—tThere is little doubt that these large Thracia-like forms are related to Pseudomultha petersoni from the Cardalitos shales whose lucinoid affinities are clearly established. They differ principally from petersom by their much larger size and more central beaks. Some specimens show faint impressions of the pustules of the interior of the valves overrun by the coarse lines of growth, indicating that the valves were quite thin. There are no marks of the adductor muscles or of the hinge armature. The largest valves measure 120 millimeters in length. Locality and Geologic Occurrence.—Lower Miocene, railroad cuts between Amen and Playas, Ecuador. Pseudomiltha ? insleyi Spieker Phacoides (Pseudomiltha?) insleyi Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, pp. 132, 133, pl. 7, fig. 11 An example from Zapotal may belong to this species. Spieker compared insleyi with Miltha (Megax nus) gluminda Woodring from Bowden. It is not certain that insleyi is really a lucinoid as our specimen from Zapotal (if correctly determined) bears considerable resemblance to a Cyclinella. Spieker does not men- tion a lunule in his description but this feature is often only poor- ly differentiated on some species of Cyclinella. In our Zapotal shell, a lunule seems to be present but this area is nearly covered with gypsum. Locality and Geologic Occurrence.—Lower Zorritos forma- tion, Ridge between Ques. Heath and Charan (Spieker ; Zapotal. Genus CODAKIA Scopoli Codakia, sp. Three examples of a small to medium-sized Codakia were col- lected at Zapotal. The hinge has been destroyed and conse- quently the subgenus to which they belong, cannot be determined. 97 OLSSON: PERUVIAN MIOCENE 97 The sculpture is fine, regular, consisting of small radials and is evenly imbricated by fine, concentric threads. The sculpture be- comes coarser, with the radials more widely spaced on the an- terior submargins. This sculpture is similar to that of Codakia orbicularis Linné while in most species of Jagomia, the radials are usually stronger and more cord-like in form. Our largest specimen which is very badly crushed is about 30.00 millimeters in height. Locality and Geologic Occurrence.—Lower Zorritos forma- tion, Zapotal. Superfamily CARDIACEA Family CARDITDAE Genus CARDIUM Linné Subgenus DINOCARDIUM Dall Cardium (Dinocardium) ecuadorialis, n. sp. Plate 8, fig. 1 Shell of medium size. subcircular with broad, full, convex umbones; anterior and ventral margins evenly rounded; the pos- terior, obliquely subtruncate, becoming vaulted or obtusely angled at its junction with the dorsal margin; the posterior-dorsal area well defined, smooth, distinguished by the absence of ribs; sculptured with about 29 strong ribs, of which the anterior 6 are obliquely flattened, smooth, the following 12 to about the middle of the shell are scaley, wrinkled (lepidote of Dall), the remaining 11 are more rounded in form and separated by deeper grooves; the posterior-dorsal area is smooth, with few, very faint radial or rib-like markings; interior unknown. Length, 39 mm.; height, 41 mm.; semidiameter, 13.5 mm. Remarks.—This shell resembles a young Cardium robustum Solander but the beaks and umbones are high and fuller, and the posterior area is nearly smooth. It is probably the first true Dinocardium described from the Pacific region. The Peruvian specimens have lost their external sculpture but the impression of the ends of the ribs along the ventral margin are the same in number as those of the Ecuadorian examples and they have the smooth dorsal areas of ecuadorialis. Two or more undescribed species of Dinocardium occur in the Lower Miocene deposits of Panama and Colombia. A spe- 98 BULLETIN 68 98 cies nearly as large as robustwm is common as casts in certain lower Miocene sandstones near Alhajuela Panama, mapped by Reeves and Ross® as ? Gatun. It has 30 to 31 ribs. Another species is common in the lower Miocene of the Sinu district of northern Colombia”. It differs from ecuadorialis in having 35 ribs instead of 29. The Cardiwm chipolanum Dall® from the Chipola Miocene of Florida has but 24 ribs which are therefore wider and flatter. In the same horizon occur taphrium Dall®* and waltonianum Dall®* both having more numerous ribs. Locality and Geologic Occurrence.—Lower Miocene sand- stones along uncompleted railroad between Playas and Amen, Ecuador. Upper Zorritos, Punta Picos ridge. Subgenus TRACHYCARDIUM Morch Cardium (Trachycardium) zorritensis Spieker Cardium (Trachycardium) zorritencis Snicker. 1922 Johns Hopkins University, Studies in Geology. No. 3. p, 134 pl. 7. fig. 12 Original description.—Shell thin. inflated. subequilateral. Anterior mar- gin rounded, not produced; ventral margin rornded; posterior margin slightly produced. Umbones high, inflated. narrow. Surface generally convex except on either side of the beaks where a slight concavity leads into the poorly defined areas. Sculpture of 32 smooth inverted V-shaped ribs with V-shaped interspaces about equal in width; in the right valve of worn specimens the posterior five ribs are roughly bifid for their entire length and in the left valve a similar suleation of the posterior ribs is evident, but some of the bifurcations are still more uneven, giving one of the paired ribs the appearance of a secondary interstitial rib. These irregular ribs represent the bases of spines which are lost on the specimens available, Area, teeth, and inner shell unknown. Length, 31.25; height, 33.5; (semi) diameter, 15 mm.—Spieker, 1922. Remarks.—This species is known only from Spieker’s types. Locality and Geologic Occurrence.—Lower Zorritos formation, Zapotal. Cardium (Trachycardium) peruvianum Spieker Cardium sp. ind., Nelson, 1870, Trans. Conn, Acad. Sci.. vol. 2. p. 203 Cardiuwm (Trachycardium) peruvianum Spieker. 1922 Johns Hopkins University, Studies in Geology, No. 3. p. 135, pl. 8. fig. 1. Original description.—Shell large, inflated, evenly rounded. Marginal 90Reeves and Ross, 1930, A geologic study of the Madden Dam project, Alhajuela, Canal Zone, U. S. Geol. Survey, Bull. 821-B, p. 14. 91Woodring, 1928, Carnegie Institution of Washington, No. 385, p. 79. 92Dall, 1900, Trans. Wagner Free Institute, vol. 3, pt. 5, p. 1098, pl. 40. fig. 8; Gardner, 1926, U. S. Geol. Survey, Prof. Paper 142-C, p. 188, pl. 238, fig. 9. 93 94Dall, 1900, op. cit., p. 1098, pl. 40, fig. 9; p. 1098, pl. 48, fig. 19; Gard- ner, 1926, op. cit., p. 189, pl. 238, fig. 7 and fig. 8. 99 OLSsoN: PERUVIAN MiocENE 99 outline unknown, Umbones prosogyrate, broad and full dorsally, tapering rapidly terminally. Surface very convex, evenly rounded, excepting the usual excavations before and behind the beaks. Seulpture of about 50 sharply defined, square, strong ribs, with channelled interspaces equally broad; spines may have existed, but the specimens available are worn. Area and hinge normal. Inner margins unknown. Length, 46; height, 46; (semi) diameter, 18,5 mm.—Spieker, 1922. Remarks.—-Casts and distorted specimens of a large Cardium were found at Tucillal. They probably belong to this species but certain identification is not possible. Locality and Geologic Occurrence.-—Tumbez formation, Tucillal, Subgenus TRIGONIOCARDIA Dall Cardium (Trigoniocardia) hannai, n. sp. Plate 8, figs. 4, 9, 10, 11 Cardium (Trigoniocardia) affinis Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p, 136, pl. 8, fig. 3. (not of Nelson, 1870). Shell small, subquadrate, solid; umbones full, wide, ending in the small, closely adjacent and slightly prosogyrate beaks ; shell strongly convex, the greatest inflation usually in the middle of the valves or just above; umbonal slope more or less angled with the dorsal slope appressed, sloping and sculptured with smaller ribs; when viewed from within, the out'ine formed by the mar- gins of the shell is a broad parallelogram, the anterior and poste- rior side meeting the dorsal and ventral margins at oblique angles ; sculpture of about 19 ribs, there being a set of 12 anterior to the umbonal angle and 7 smaller ones on the posterior-dorsal slope; the central and anterior set of 12 ribs are square in sec- tion and usually nearly twice the width of the channelled inter- spaces ; the ornamentation of the ribs is usually variable on the type specimen, they are smooth on the ventral part, have a group of 2, 3 or 4 tubercles on the center and are probably again smooth on the umbone (slightly exfoliated) ; on other specimens the tubercles occur on the ventral part of the ribs also; the dorsal set of 7 ribs are smaller, the interspaces less deep and ornamented with smaller tubercles; interspaces are sculptured with strong cross threads ; hinge normal with strong lateral teeth. 100 BULLETIN 68 100 Height, 12.5 mm.; breadth, 11 mm.; semidiameter, 6.5 mm. Locality and Geologic Occurrence.—Lower Zorritos forma- non, (Orbe. Ikey (Cirra, Cardium (Trigoniocardia) spiekeri Hanna and Israelsky Plate 8, figs. 3, 7 Hemicardia affinis Nelson, 1870, Trans. Conn. Acad. Sei., vol. 2, p. 204. (not Miinster, 1835). Cardium (Trigoniocardia) affinis Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 136, pl. 8, fig. 2. Cardium spiekeri Hanna and Israelsky, 1925, Proce. Calif, Acad. Sci., 4th series, vol. 14, p. 62. (new name for affinis Nelson). Original description.—Two specimens were found, belonging to this genus, and related to H. obovalis Carp., but. may easily be distinguished from that species by the following differences. Ribs much finer, more elevated, and the spaces between them broader. The two species differ also in the proportional measurements. Length, 19.1 millim,; breadth, 10.4 millim.; height, 10 millim.—WNelson, 1870. Shell small to medium size, inflated, obliquely subovate; um- bones full, lying in an axial line which extends obliquely along the smoothly rounded umbonal slope from the beaks to the posterior-ventral extremity and dividing the shell into two nearly equal and similar parts; beaks small, closely adjacent, no dif- ferentiated posterior-dorsal area; ribs about 21 in number, are quite broad, flattened and usually smooth, separated by somewhat narrower, channelled interspaces which are sculptured or scal- loped with strong, evenly spaced cross-threads. Height, 18 mm.; breadth, 18 mm.; semidiameter, 8.5 mm.; oblique length, 20.5 mm. Height, 20 mm.; breadth, 19 mm.; semidiameter, 8.5 mm.; oblique length, 22 mm. Remarks.—This species is common at Tucillal but as far as known does not occur at any other horizon. It is related to C. obovale Sowerby of the recent West Coast fauna but differs from the recent shell, in being widely impressed dorso-ventrally and by its wide, more flattened ribs and narrower interspaces. Spieker has figured this species with another but smaller Trigont- ocardia (C. hannai) from the Lower Zorritos. Locality and Geologic Occurrence-—Tumbez formation, Que. Tucillal at Zorritos, 101 Oxtsson: PERUVIAN Mi1ocENE 101 Subgenus AMERICARDIA Stewart Cardium (Americardia) stewarti, n. sp. Plate, 8, fig. 8 Shell small, solid, subquadrate with a sharp angular posterior ridge; umbones full, ending in the small, scarcely prosogyrate, adjacent beaks; posterior-dorsal slope flattened to impressed, sculptured with somewhat smaller ribs; rest of the shell broadly convex across the middle, then sloping rapidly to the anterior submargins ; ribs about 26 on left valve, there being 16 anterior to the posterior ridge and 10 on the posterior-dorsal slope; the ribs are flattened on top, about twice the width of the narrow channelled interspaces; the ribs may be smooth or sculptured with coarse, elevated growth-lines and on some ribs by an occa- sional tubercle; interspaces are sculptured or scalloped as in Trigoniocardia with strong cross-threads; the ribs on the poste- rior-dorsal slope are smaller than the others but increase in size towards the hinge-line; hinge normal with the anterior lateral quite close to the cardinal. Length, 9 mm.; height, 10 mm.; semidiameter, 4 mm. Remarks.—Besides the Holotype, our collection contains three other, but imperfect, specimens. Like Cardium burns% Dall®? from the Chipola Miocene, this little species seems to stand inter- mediate between Americardia of Stewart (genotype Cardium medium Linné) and typical Trigoniocardia (genotype Cardium graniferum Sowerby) having the striated interspaces and occa- sional tuberculated ribs of Trigoniocardia and the form and flattened ribs of Americardia. Hinge like Caridum (Americar- dia) medium with the anterior lateral closely adjacent to the cardinal, the left anterior lateral with a deep pit along its in- ferior side for the lodgment of the anterior lateral of the right valve. The stratigraphic position of this species cannot be definitely fixed. It was collected with Bursa freya from soft, yellowish sandstones capping Heath shales along the divide between Que- brada Seca and Quebrada Conchudo-Bravo, just north of the auto road. These beds may represent a sandy horizon in the 95Dall, 1900, Trans. Wagner Free Institute, vol. 3, pt. 5, p. 1101, pl 48, fig. 15; Gardner, 1926, U. S. Geol. Survey, Prof. Paper No. 142-C, pt. 3), 10, IOs yall, Beis aay, wee 102 BULLETIN 68 102 upper Heath or late Upper Oligocene or possible a small remnant of lower Miocene beds of basal Zorritos age. This species is named for Dr. Ralph B. Stewart, author of the subgenus Americardia. Locality and Geologic Occurrence.—see above. Superfamily VENERACEA Family VENERIDAE Genus CLEMENTIA Gray Subgenus CLEMENTIA Gray Clementia (Clementia) dariena Clonrad Meretrix dariena Conrad, 1855, U. S. Pae. R, R. Expl., vol. 5, pt. 2, appendix, p. 328, pl. 6, fig. 55. Clementia dariena Gabb, 1881, Journ. Acad. Nat. Sci. Phila., vol. 8, p. 344, pl, 44, figs. 16, 16a. si Be Dall, 1903, Trans. Wagner Free Inst., vol. 3, pt. 6, p. 1235. ae ae Toula, 1909, Jahrb. der K-K, Geol. Reichsanstalt, Wien, vol. 58, pp. 725, 757, pl. 27, figs. 9, 10. Clementia darieana Brown and Pilsbry, 1911, Proc. Acad, Nat. Sci. Phila. vol. 63, p. 371, pl. 28, fig. 1. oe Olsson, 1922, Bulls. Amer. Pal., vol, 9, p. 404, pl. 31, fig. 4. tS os Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 141, pl. 8, fig. 5. ae He Woods, 1922, Bosworth Geology of North-West Peru, p. 113, pl. 20, fig. 4. ie se Maury, 1925, Bulls. Amer, Pal., vol. 10, p. 293, pl. BY een ec a es Pa ee se Harris, 1926, in Waring, Johns Hopkins Univer- sity, Studies in Geology, No. 7, p. 110, pl. 20, fig. 8. BS a0 Palmer, 1927, Pal. Americana, vol. 1, p. 410, pl. 26, figs. 6, 13-20. Clementia dariena dariena Weisbord, 1929, Bulls. Amer. Pal., vol. 14, - p- 256, pl. 5, fig, 1. Clementia (Clementia) dariena dariena Woodring, 1926, U. 8S, Geol. Survey, Prop. Paper 147-C, p. 34, pl. 14, figs. 6-11. Clementia (Clementia) dariena Anderson, 1929, Proc. Calif. Acad. Sei., 4th series, vol. 18, p. 167. Harvella? sp.-ind. Nelson, 1870, Trans. Conn. Acad. Sci., vol. 2, p. 201. ?Clementia brasiliana Maury, 1925, Brasil Servicio geol. mineral. Mon. vol. 4, p. 422, pl. 24, fig. 3. Original description.—Obtusely and obliquely subovate; ventricose; in- equilateral: anterior extremity angulated, and situated much nearer the beak than the base; anterior dorsal line straight and oblique; beak not prominent; basal and posterior margins profoundly rounded.—Conrad 1856, 103 OLSSON: PERUVIAN MIocENE 103 Remarks.—Detailed description of this common Miocene species may be found in Palmer’s Monograph and in Woodring’s excellent paper on the genus Clementia. Clementia dariena 1s widely distributed in Peru ranging through the whole Miocene system but not common at any locality. The shell varies in out- line from nearly circular to elongate ovate. Young specimens 35 millimeters or less high, have the concentric undulations quite strong and regularly spaced about 2.5 millimeters apart but they usually become obsolete or irregular as the shell becomes mature. The valves are strongly convex. Clementia peruviana Olsson, the late Eocene and Oligocene percursor of dariena along the West Coast, is a smaller, less convex species with much finer and more irregular sculpture. The specimen figured by Spieker belongs to the Nelson collec- tion at Yale and was recorded by Nelson as Harvella. Locality and Geologic Occurrence.—Montera formation, Zone A, Que. Montera, Sechura. Zorritos group, Lower Zorritos of Que. Zapotal. Upper Zorritos, Punta Picos, Zorritos. Tumbez formation, Que. Tucillal at Zorritos (Nelson coll. and Olsson.) Lower Miocene near Bajada and Amen, Ecuador (Woodring Pp. 35). Genus DOSINIA Scopoli Section DOSINIDIA Dall Dosinia (Dosinidia) delicatissima Brown and Pilsbry Plate 9, figs. 3, 4,5 Dosinia delicatissima Brown and Pilsbry, 1912, Proe. Acad, Nat. Sei. Phila., vol. 64, p. 516, pl. 26, fig. 1. Dosinia (Dosinidia) delicatissima Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 140. Dosinia (Dosinidia) delicatissima Palmer, 1927, Pal. Amer., vol. 1, p. 63, pl. 17, figs. 1, 9. Spieker appears to be right in referring the small to medium- sized Dosinia common at Zapotal to Dosinia delicatissima Brown and Pilsbry, first described from the Gatun Miocene. The shells are high, quadrate to subcircular in form with a straight but short hinge margin, a long, straight, lunular edge and a straight, posterior side meeting the dorsal margin to form a rounded right angle. The shell is thin and sculptured with very narrow, even circular bands. The lunule is subelliptical, smooth with a raised, pouting margin. 104 BULLETIN 68 104 Specimens from the Ecuadorian Miocene are larger than the Zapotal examples, more quadrate in form, with a longer, straight- er, hinge margin. The texture is usually very thin, becoming of paper thickness on the middle of the valves. Sculpture is even, somewhat finer than on Dosimia dunkeri Philippi of the recent Vest Coast fauna. Grzybowsk1’s®® Dosima lenticula is an internal mold described from Grau. It is a small, subcircular shell, somewhat longer than high and about 30 millimeters in length. Grzybowski’s figure shows a large pallial sinus reaching nearly to the middle of the valves and has a peculiarly deep, concave upper side, quite dif- ferent from any Dosinia known to me. Locality and Geologic Occurrence.—Zorritos group, Lower Zorritos, Que. Zapotal. Miocene sandstones in railroad cut half- way between Amen and Playas, Ecuador. Dosinia (Dosinidia) illesca, n. sp. Plate 9, figs. 1, 2 Shell of medium size, solid and strongly convex; the outline is nearly circular, a little longer in the lower ventral half and slightly shorter along the hinge-line; beaks small, adjacent and curved forward over the deep, cordate lunule; umbones not prominent, passing gradually into the full convexity of the shell which is situated about the middle of the valves; lunule broadly cordate, smooth and deeply sunken, approximately twice as long as wide; shell rather solid, with the surface sculptured as in Dosima grandis Nelson with wide, concentric bands, strongest on the anterior and posterior submargins, much wider or sub- obsolete on the center of the valves; on the type specimen they measure about 1.50 to 1.75 millimeters in width on the center of the shell disk; hinge typical of the genus with a small anterior cardinal, a larger middle cardinal and a long, bifid posterior cardinal tooth in the right valve ; interior of shell cavity unknown. Length, 63 mm.; height, 60 mm.; diameter, 39 mm. Remarks.—This species is remarkable for the great, relative convexity of its valves. It probably represents an early form of the Dosinia grandis - ponderosa group, the surface of the valves having a similar sculpture of wide, concentric bands. From 96Grzybowski, 1899, Neues Jahrb., Beil. Bd. 12, p. 639, pl. 17, fig. 11. 105 OLSSON: PERUVIAN MIOCENE 105 young examples of grandis. this species is easily distinguished by its great convexity, its less circular form, straighter poste- rior side and shorter, often ascending hinge-line. ; Locality and Geologic Occurrence.—Montera formation, near Tric Trac Point, Bayovar; Que. Montera, Sechura. Dosinia (Dosinidia) grandis Nelson Dosinia grandis Nelson, 1870, Trans, Conn. Aead., vol, 2, p. 201. Dosinia (Dosinidia) grandis Spieker, 1922, John Hopkins University, Studies in Geology, No. 3, p. 138, pl. 8, fig. 4. Dosinia (Dosinidia) titan Maury, 1925, Bulls. Amer. Pal., vol, 10, p. 139, pl. 24, figs. 1, 2; pl. 25, fig. 3. Dosinia (Dosinidia) grandis Palmer, 1927, Pal. Amer., vol, 1, p. 275, pee eZ ple lo ess pl. 20 pig ies ply ao, mes. le 23, Original description.—Shell large, solid, sub-equilateral; length and breadth neary equal; broadest just above the middle line. Beaks elevated, nearly central, curved inward and forward. lLunule heart-shaped, very deeply impressed, two-thirds as wide as long, marked by striations, which become finer as they pass into it. Anterior end short. Anterior and poste- rior ends nearly equally rounded. Ligament large; scar long, striated longi- tudinally. Surface covered by a thick epidermis, and marked by broai, flat, concentric ribs, which become larger and smoother over the middle of the shell, but not wholly obsolete. With the epidermis removed the shell still shows the striations, especially about the beaks. Hinge line nearly straight, very broad. The median tooth (cardinal) of the right valve is large and pointed; posterior cardinal deeply bifid. Lateral tooth large, nearly as long as the posterior cardinal and parallel with it, In the left valve the median cardinal is bifid throughout the upper half of its length. Hinge area forming a very obtuse angle with the ligament area. Muscular scars and pallial impression not observed. A young and a full grown specimen give the following measurements: Young, Length, 46.05 mm.; breadth, 47.1mm.; height, 22.6 mm. Mature, if 95.60 mm. ; Ge 95.2 mm.; Ee 47.2 mm, Remarks.—This species was well described by Nelson who compared it with Dosinmia ponderosa Gray, its nearest related form, differing from the recent shell by its coarser, concentric sculpture and heavier valves. Both Spieker and Palmer have figured the lectotype from the Nelson collection. According to Palmer, Dosinia titan described by Maury from the Springvale beds of Trinidad cannot be separated specifically from grandis. Dosina grandis is common in the Tucillal beds but all our specimens have the surface deeply weathered and exfoliated especially over the umbonal region. A specimen from Sechura and probably of Pliocene age has exceedingly coarse, concentric bands, nearly two millimeters wide on the middle of the valves. 106 BULLETIN 68 106 Casts of a large Dosinia are often common in the Mancora tab- lazo deposits but it is not known to which species they belong. Darwin (Geol. Observations, p. 129) records a large Dosimia as ponderosa from Coquimbo, Chile, which may possibly be this species but the figure given by Philippi in his Versteinerungen, Chiles, pl. 14, fig. 5 was made from a recent example of ponder- osa. Steinmann and Moricke® collected this large Dosimia at Caldera, Chile, in beds of the same age as those of Coquimbo. According to Moricke, they agree well in size and form with the recent species but the fossil form has a heavier shell and stronger hinge. It-seems probable that the Chilian shell is more closely related to D. grandis than to the recent Panamic ponderosa. In the recent fauna, ponderosa finds its southern limit at Paita but I have seen no Peruvian specimens comparable in size to those of Lower California and the West Coast of Mexico. Spieker records grandis from the Variegated beds near Boca Pan but the only specimens of true grandis which we have found in the Zorritos region, are from the Tumbez formation of Que- brada Tucillal. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Sechura formation, Que. Montera, near Bayovar. Genus PITARIA Romer Subgenus PITARIA s. s. Pitaria (Pitaria) sapotana, n. sp. Plate 10, fig. 6 Shell of medium size, thin, oval, convex ; umbones very wide, merging into the full convexity of the shell, located about the middle of the valves; the beaks are small, not quite touching and slightly coiled; the dorsal-posterior side is vaulted or curved, sunken or depressed along the hinge-margin into the narrow escutcheon; anterior side slightly produced, flattened to im- pressed, the lunule scarcely showing on the holotype; the pos- terior side rounded; the ventral side well-rounded to nearly straight ; external sculpture consists of rather coarse, crowded, subregular growth-lines ; interior unknown. Length, 40 mm.; height, 36 mm.; diameter, 23.5 mm. Remarks.—This species should be easily distinguished from related forms by the strongly convex or vaulted posterior-dorsal side. The hinge is not exposed but it is probably a true Pitaria 297MG6ricke, 1896, Neues Jahrb. f. Min. etc., BB. 10, p. 585. 107 OLsSson: PERUVIAN MIocENE 107 related to the sayana-morrhuana group. The specimens from Quebrada Hiqueron are small and may possibly belong to a different species. Locality and Geologic Occurrence.—Lower Zorritos of Zapo- tal, Quebrada Hiqueron? Subgenus PITARELLA Palmer Pitaria (Pitarella) tumbezana, n. sp. Plate 10, figs. 1, 3 Amiantis incrassata var. ovoidalis Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 146, pl. 9, fig. 5. (not of Sacco 1900). Shell of medium size to large, thin, inflated, ovate; umbones rather wide, full, passing into the maximum convexity of the valves which is just above the middle of each valve; beaks small, nearly touching and slightly coiled, situated at the anterior one- fourth; dorsal side slightly convex, sunken or depressed along the margin with a long, narrow ligamental groove; anterior side slightly produced, the lunular region nearly straight ; lunule wide- ly cordate and feeble, defined by an impressed line; basal margin widely rounded, passing into the more narrowly rounded pos- terior end; surface chalky or sculptured with simple growth lines; hinge of right valve with the socket for the left, anterior lateral situated on the hinge plate fairly close to the anterior cardinal tooth; interior of shell cavity unknown. Length, 42 mm.; height, 35 mm.; diameter, 25 mm. Length, 38 mm.; height, 31 mm.; diameter, 21.5 mm. Length 49 mm.; height, 41 mm.; diameter, 32 mm. Remarks.—Two fragmentary right valves from the Cardalitos shales of Sechurita show a part of the hinge structure. The hinge plate is quite large and solid, with the socket for the in- sertion of the left, anterior lateral, situated close or but a short distance in front of the cardinal tooth as in Pitarella and is prob- ably a member of that subgenus rather than Pitaria, sensu stricto. Externally tuwmbezana resembles gatunensis Conrad of the Caribbean Miocene but the anterior side is shorter, less depressed and the beaks and umbones of the shell more posterior in posi- tion. The form appears to be variable, some shells from Sechu- rita being almost subcircular but this condition may be due in 108 BULLETIN 68 108 part to crushing as they are poorly preserved, broken and rece- mented by gypsum, The average size is about 40 millimeters in length but a large specimen from Quebrada Heath is nearly 50 millimeters in length. The shell figured by Spieker as Amyantis incrassata var. ovoidalis Sacco (an European Eocene species) is in the Nelson collection at Yale, and represents merely a large tumbezana, the specimen being very similar to the large shell from Que. Heath referred to above. Locality and Geologic Occurrence——Cardalitos formation, Sechurita, Headwaters of Que. Heath, Que. Charan. Subgenus HYSTEROCONCHA Fisher Pitaria (Hysteroconcha) humboldtiana, n. sp. D Plate 11, fig. 1 Shell rather large, solid, depressed, subelliptical in form; um- bones slightly flattened, ending in the forward pointing and slightly curved beaks which are situated near the anterior one- fifth; dorsal-posterior side little convex, straighter in the pos- terior portion; the ventral margin is broadly curved with the anterior and posterior extremities narrowly rounded; anterior side straight and rather long, the lunule itself small, narrowly elliptical and defined by an impressed line; surface is sculptured with very strong, elevated, rib-like, concentric folds which are spaced about 3.75 mm. apart on the lower, middle part of the disk, closer on the umbones and near the ventral margin; they are rounded on top, inclined slightly dorsally and separated by deep, wide interspaces; along a line just below the umbonal angle, the concentric lamellae become abruptly narrowed, lower and changing their di-ection across the umbonal angle form a line, the ends of the heavier lamalle being angled or possibly forming incipient spines; posterior-dorsal slope flattened to ex- cavated (weathered on our specimen) and probably sculptured with the continuation of the narrow lamalle; hinge of left valve typical of Pitaria with a strong, central cardinal tooth, a nar- row anterior cardinal and a strong anterior lateral; ventral mar- gin smooth, 109 OLSSON: PERUVIAN MIOCENE 109 Length, 55 mm.; height, 46.50 mm.; semidiameter, 8 mm. Remarks.—This beautiful species is represented by a single specimen which is not quite perfect. The concentric lamellz are unusually strong, there being about 14 over the lower 40 millimeters of the valve surface. They are closer spaced on the umbos which are weathered and smooth on my specimen. Along a line just below the umbonal angle and corresponding to the first row of spines in Hysteroconcha, some of the lamellze be- come angled and narrowed as they cross the umbonal slope. In- terior concealed except the hinge and a small part of the ven- tral margin. Three or four species of Hysteroconcha occur along the West Coast of South America, P. lupanaria Lesson sometimes reaches a length of about 70 millimeters. None of the recent species are related to humboldtiana, all having more convex, thinner valves and finer sculpture. Locality and Geologic Occurrence-—lumbez formation, Que. Tucillal near Zorritos. Section LAMELLICONCHA Dall Pitaria (Lamelliconcha) petersoni, n. sp. lene Wil, sys Shell subtrigonal with high, narrow umbones and nearly erect beaks situated at the anterior one-third; anterior and ventral margins regularly rounded; posterior-dorsal side nearly straight, descending, the umbonal slope somewhat angled and with the dorsal-posterior submargins contracted and flattened; the pos- terior extremity is subtruncate to square in form; surface sculp- ture consists of fairly regular, elevated, concentric lamellz, wide- ly spaced as in alternata Broderip; interspaces flattened to exca- vated, smooth or marked with fine growth-lines; ventral margin smooth; lunule small, feebly defined; hinge apparently normal. Length, 38.25 mm.; height, 33.5 mm.; semidiameter, 9 mm. Length, 37 mm.; height, 34.5 mm.; semidiameter, I1.5 mm. Length, 37 mm.; height, 31 mm.; semidiameter, 9.5 mm. Remarks.—Possibly this shell should be considered as a va- riety of circimata (Born) but all our specimens differ constantly by their high, more trigonal shell and squarish, truncated pos- terior extremity. The concentric lamellz are widely spaced as in alternata Broderip, the West Coast variety of circinata. 110 BULLETIN 68 110 Locality and Geologic Occurrence.—Lower Zorritos, Que. Zapotal. Pitaria (Lamelliconcha) aequicincta Spieker Plate 9, fig. 6; Plate 11, figs. 5, 7 Cytherea planivieta Grzybowski, 1899, Neues Jahrb,, Beil. Bd. 12, p. 639, pl. 19, fig. 3. (not Guppy). Pitaria (Lamelliconcha) cora var, aequicincta Spieker, 1922, Johns Hopkins University, Studies in Geology No. 3, p. 149, pl. 9, figs: 6, 7: Original description.—Shell thin, large, somewhat compressed. Anterior margin broadly rounded; ventral margin elliptical, its junction with the posterior margin in the form of an apically rounded acute angle. Surface generally convex, but the shell is not highly inflated. Sculpture of fine, nearly even concentric ribs, which are slightly steeper on their dorsal slopes, and which appear very finely and sharply graven. There is no radial striation. The cardinal areas are poorly defined. Inner shell unknown except that the anterior muscle scar is but slightly impressed, the posterior not at all, and that the valve-margins are smooth. Length (large specimen ) 49.5; height 38; (semi) diameter 10 mm. Length (smaller specimen) 31,5; height ?; (semi) diameter 6 mm.—Spieker, 1922. Remarks.—Spieker’s types are two casts, one showing part of the external shell. It is common in the Upper Zorritos sand- stones but in breaking the rock, casts and internal molds are usu- ally only obtained in the course of collecting. It is distinguished by its rather large size, pointed, erect beaks, narrowly rounded to subpointed posterior extremity and bulging or rounded an- terior and ventral sides. The concentric sculpture is usually feebly impressed upon the otherwise smooth casts. Well preserved examples such as illustrated by fig. 7, have the surface sculpture of Lamelliconcha and consist of regular, ele- vated and thickened concentric ribs separated by deep, grooved interspaces. Spieker described aequicincta as a variety of cora Brown and Pilsbry but its constantly larger size, different form and sculpture show that Peruvian shell is specifically distinct from the Gatun. Grzybowski’s Cytherea planivieta from the Cardalitos shales of Grau may represent this species but his figure shows the beaks as being more erect and central and the anterior-ventral side as more rounded, Our specimens measure as follows: Length, 44.5 mm.; height, 34 mm.; diameter, 20.5 mm. Length i741 OLSSON: PERUVIAN MIocENE 111 38 mm.; height, 30 mm.; diameter, 16 mm. Length, 52 mm.; height, 38 mm. ; diameter, 21 mm. Locality and Geologic Occurrence—Upper Zorritos sand- stones near Punta Picos. Cardalitos formation. Grau (Grzy- bowsk1i). Genus CHIONE Megerle von Miuhlfeld Subgenus CHIONE, s. s. Section CHIONOPSIS, n. sect. Type.—Chione amathusia Philippi The following is a description of the section Chionopsis : Shell of moderate size to large; right posterior and middle, left cardinal teeth bifid or grooved, sometimes the others; resi- lium very narrow with the ligament not deeply inserted and sep- arated by a narrow, linear nymph; shell usually thinner than amongst the true Chiones; pallial sinus well developed; lunule equal or discrepant in size. its margin strongly crenate. Remarks.—Clearly two quite distinct groups of shells have usually been classified amongst the typical Chiones. Chione s. s. (genotype Chione cancellata Linné) as here understood, includes but a few species principally belonging to the recent faunas. Chione cancellata, the genotype, is East American and West In- dian with Chione succincta Valenciennes and the striking Chione compta Broderip along the West Coast of South America. They are typically solid, trigonal shells with simple cardinals, exca- vated escutcheon strongly defined by an angled ridge, strongly cancellated sculpture, smooth or only feebly crenate lunular mar- gin and practically entire pallial line. To Chionopsis belong most of the fossil and recent species of Chione and it represents an older and possibly different line of descent. In the typical members as amathusia, gnidia, of the West Coast, pubera Valen- ciennes of the Caribbean, the shells are of ordinary thickness, quite convex with full, inflated umbones. One or more cardinal teeth in each valve are distinctly bifid or grooved. The lunule is often quite unequal in each valve and amongst such fossil species as Chione variabilis Nelson the left lunule is much larger, its margin deeply impressed or concave and fitting beneath the 112 BULLETIN 68 112 other. The lunular margin is always coarsely crenate. A few of the many fossil species which belong to Chionopsis include the following, rowleei Olsson from Costa Rica, atlanticana An- derson from Colombia, walli Guppy from Trinidad and para- guanensis H. K. Hodson from Venezuela. Chione (Chionopsis) propinqua Spieker Plate 11, figs. 2, 3. 8 Chione (Chione) propinqua Spieker, 1922, Johns Hopkins University, Studies in Geology No. 3, p. 152, pl. 9, fig. 12. Original description.—Shell of medium size, subtrigonal, inflated. Ante- rior margin rounded, ventral margin arcuate. Posterior margin forms a distinct angle with the ventral margin, and is almost straight. Umbones prosogyrate, anterior in position. General surface markedly convex; a pronounced posterior carina separates the narrow posterior surface of the shell from the rest. Concentric sculpture of the prominent lamelle typical of the group, distinctly spaced, erenulate on the under surface. Radial sculpture of ribs which show a somewhat indistinct yet recognizable pairing on the disc; there are less prominent ribs between the pairs. Lunule not clearly visible on specimens studied, but it appears to be impressed and configured much as in C. walli Guppy, C. woodwardi Guppy, and related species. The esecutcheon is long, somewhat broad. Inner margin finely erenulate. Length, 24; height, 21.5; (semi) diameter, 8.5 mm.—Spieker, 1922. Remarks—In common with most fossils from the Zapotal horizon, this species is usually poorly preserved, the surface fea- tures being obliterated or partly destroyed through the replace- ment of the original calcium carbonate of the shell by gypsum. Spieker’s figure is therefore rather misleading and does not show the real characteristics of the species. Chione propinqua is re- lated to Chione walli Guppy but is easily distinguished by being less rounded, the posterior extremity is longer and more produced and the posterior-dorsal margin is straighter. The sculpture of propinqua is coarser, the concentric lamelle being stronger, less numerous, becoming more elevated, foliaceous along the poster- ior-dorsal or umbonal slope. In walli there is a sharp division between the sculpture on the center of the disk with that border- ing the posterior-dorsal slope, the simple ribs of the umbones not becoming double as they do anterior of this line but remain- ing simple and hence coarser nearly to the ventral margin. This area covering about a fifth of the surface, remains similarly sculptured across the umbonal slope to the region of the escutch- eon. In propinqua, this area is also wide but further subdivided so that the posterior half is sculptured only with small, subdued 113 OLSSON: PERUVIAN MIOCENE 113 radials as far as can be determined from the poor preservation of the material. The sculpture elsewhere is similar to that of wall. Chione paraguanensis H. K. Hodson®* from Locality 2207, Cantaura, Venezuela (Lower Miocene) is nearer propinqua than walli. Mrs. Hodson carefully compared her types with propinqua. The Venezuelan shell although closely related to Spieker’s species may be distinguished by certain constant dif- ferences, such as its narrower umbones, finer concentric sculp- ture which does not become as strongly foliaceous on the um- bonal ridges, the posterior extremity is more cuneate or pointed while in propinqua the posterior extremity is obliquely truncate. A Chione common in the Lower Miocene beds of Barrancas near Punta Arenas, Costa Rica and compared to meridionalis Sower- by from Patagonia and walli Guppy by Romanes*® may be iden- tical or a varietal form of propinqua. Locality and Geologic Occurrence.—Lower Zorritos of Zapo- tal, Que. Charan, sta. Io. Chione (Chionopsis) cf. costaricensis Olsson Plate 10, fig. 8 ef. Chione costaricensis Olsson, 1922, Bulls, Amer. Pal., vol. 9, p. 417. ef. Chione (Chione) costaricensis Palmer, 1917, Pal. Amer., vol. 1, p. 356, pl. 40, fig. 10, Our collection contains an imperfect specimen from the Var- iegated beds of Quebrada Picos which appears to be closely re- lated to this Costa Rican species. The posterior-side is slightly flexuous, the posterior extremity, wide and sharply truncate. Surface sculpture consists of low, regular, concentric lamellar rings, their intervals being marked with fine, subregular, cord- like radial riblets which pass over the reflected, ventral face of the concentric lamellae. This sculpture seems to be somewhat smoother and less regular than on the Holotype of costaricensis but both the Costa Rican and Peruvian material being very meager, the regularity of this character is not known. Length, 32.50 mm. ; height 28.00 mm. ; semidiameter, 8.50 mm. Locality and Geologic Occurrence.—Variegated beds of Que. Picos. 98H. K. Hodson, 1927, Bulls. Amer. Pal., vol. 13, p. 62, pl. 35, figs. 2, 7. 29Romanes, 1912, Geology of a part of Costa Rica, Quart. Journ. Geol, Soe. London, vol. 68, p. 125. 114 BULLETIN 68 114 Chione (Chionopsis) variabilis Nelson Plate 12, figs. 1, 2 Chione variabilis Nelson, 1870, Trans. Conn. Acad., vol. 2, p. 202, Chione (Chione) variabilis Spieker, 122°? Johns Hopkins University, Studies in Geology No. 3, p. 150, pl. 9, fig. 9, fig. 8? Original description—A very variable species, somewhat resembling Chione gnidia Brod. and Sby., and also allied to Chione amathusia Sby. The ‘‘concentrie frills’’ are not preserved, but the position of the scars which they have left, and the arrangement of the radiating ribs, show the species closely allied to Chione gnidia. It differs from that species in having the central tooth of the hinge line more strongly fureate; in having the ligament scar less deeply im- pressed and the lunule broader. The shell is also proportionally longer and the posterior margin shorter. The crenulations of the hinge margin re- semble Chione gnidia, while the teeth more closely resemble C. amathusia ; the cardinals are, however, more divergent and apparently more rounded on the summit. Measurements as follows: length 28,42 millim.; breadth 30 millim.; 2d, length 28.85 millim.; height 19.9 millim. Specimens having a length of 50 to 60 millim, occur, but not perfect enough for measurement.—WNelson, 1870. The shel! is large, heavy, moderately but not strongly convex. The form is usually subcircular with the beaks and umbones near the anterior one-third. The ventral margin is well-rounded and nearly semicircular. Posterior-dorsal margin descending, some- what arched or curved in the middle. Anterior side a little pro- duced becoming deeply concave or depressed in the region of the lunule. Umbones wide, not prominent, with small, closely ad- jacent beaks. The posterior-dorsal area defined by a difference. in sculpture. The surface sculpture is usually destroyed, most deeply so on the umbones. The weathered umbones are smooth- ish but always show widely spaced, concentric bands or rings measuring about 5 millimeters (about 15 millimeters from the beaks) to about 7 millimeters (about 35 millimeters from the beaks) wide and the roots of small, even, primary riblets. On the ventral and central part of the shell disk where the external sculpture is sometimes partly preserved, the details of the orna- mentation is as follows: the radial riblets are usually slightly more than a millimeter in width and generally separated by slightly narrower interspaces; the primary riblets may remain simple or become mesially divided or double forming 2 secondary riblets ; an interstitial or tertiary riblet is usually introduced in the interspace which increases in size, soon equals the secondaries or divided primaries. The whole surface is further overrun with concentric frills or thin lamellae which show both on their upper 115 OLSSON: PERUVIAN MI0cENE 145 and lower faces, the radial sculpture just described. The con- centric lamelle were probably evenly spaced on the umbonal and central part of the shell surface but become irregular and crowd- ed on the ventral and anterior submargins. On such parts of the surface where the sculpture has been best preserved, the rib- lets are nearly obscured or concealed beneath crowded growth- lines. A band on the posterior-dorsal submargins is distin- guished by having a much finer radial sculpture. Hinge of the right valve with 3 cardinal teeth, no laterals, the posterior and central cardinal teeth are bifid or grooved in the middle and sep- arated from each other by a deep, wide socket for the insertion of the anterior left cardinal. The right, anterior cardinal is small, with a thin, knife-like edge. Ventral margin crudely crenulated. Lunule narrow, elliptical in form, impressed and defined by a line. The margin of the left lunule is deeply con- cave, fitting beneath the margin of the right lunule which is thus flatter in form and less deeply impressed. The lunular margins are crenulated. Escutcheon narrow, defined by a sharp angle, smooth. Length (estimated), 100 mm.; height, 86 mm.; semidiameter, 25 mm. (left valve). Length, 92 mm.; height, 78 mm.; diam- eter, 43 mm. Remarks.—Nelson’s specimens in the Yale collection are very poorly preserved and may represent more than one species. The two small shells measured by Nelson probably belong to the same form as the larger shell figured by Spieker. In this form, the shell is subcircular without a noticeable posterior flexure. The second form in the collection resembles weathered Chione amathusia but the surface being entirely destroyed, certain iden- tification from this material is impossible. The larger shell fig- ured by Spieker as variabilis, although referred to only inciden- tally in Nelson’s description, is actually the only specimen suffi- ciently well-preserved to be identifiable and consequently should be chosen as the lectotype of this species. The hinge described by Nelson from a small fragmentary specimen may not belong to this species. 116 BULLETIN 68 116 This large Chione associated with Chione angelana Spieker is fairly common at Tucillal, Zorritos. The shells are always so badly weathered that the external sculpture has been destroyed over most of the surface of the valves. The species is easily recognized by its subcircular form, low not prominent umbones and by its sculpture. The weathered smoothish umbones invari- ably show widely spaced, concentric rings and finer, regular rib- like markings. The concentric lamelle are rarely preserved. They are very thin and delicately marked or frilled by the radial riblets. The hinge of variablis and angelana is similar to that of gnidia and amathusia of the recent Panama fauna. Several large Chiones have been described from the Californian Miocene namely Chione temblorensis F. M. Anderson, securis Schumard and pabloensis Clark. Locality and Geologic Occurrence. mabe? formation, Que. Tucillal at Zorritos. Chione (Chionopsis) angelana Spieker Plate 11, fig. 4; Plate 12, fig. 3 Chione, sp. indet. B. Nelson, 1870, Trans. Conn, Acad,, vol. 2, p. 203. Chione (Chione) angelana Spieker, 1922, Johns Hopkins University, Studies in Geology No. 3, p. 152, pl. 9, figs, 10, 11. Original description.—Shell large, plump, somewhat elongate. Similar to Chione variabilis except for the following features: Anterior dorsal margin ascends sharply, making a sharp U-shaped depression in the outline before the beaks. Ventral margin broadly elliptical. Posterior margin almost angular; valves produced both anteriorly and posteriorly. Beaks more in- clined forward and much more strongly prosogyrate than in variabilis. Lunule deeper, more sharply set off, more perfectly heart-shaped. Length 55; height, 44.5; diameter, 34 mm.—Spieker, 1922. Shell large, solid, in form and general sculpture resembling Chione amathusia. The valves are strongly inflated, attaining their maximum-convexity in the middle. Umbones wide, prom- inent, with small, adjacent, coiled beaks. The external sculp- ture is usually destroyed by weathering leaving the umbones usually entirely smooth, seldom showing any radial or concen- tric markings due to the fact that the superficial layer is more easily destroyed than on variabilis. Remains of the structural layer has been observed only on the lower half of the shell. It shows a regular series of strong, Cardium-like ribs, more or less hollowed in the middle and separated by interspaces of the same 117 OLSSON: PERUVIAN MIocENE f 117 width. The perfect external sculpture is known only from a young shell (figure 4). It shows a series of concentric frilled lamelle, strongly and regularly ribbed on their lower surface as in amathusia and seemingly plain or smooth on the upper surface. They are closely spaced, the intervening area being smooth or only feebly waved by the underlying radial ribs. Lunule heart-shaped, deep. Hinge of right valve with 3 car- dinals, the posterior and central strongly bifid or grooved, the anterior one obscurely so. Remarks.—As pointed out by Spieker, this species is easily distinguished from variabilis even when poorly preserved. C variabilis is semi-circular in form with a rounded posterior mar- gin while angelana is more convex with prominently inflated umbones and pointed posterior extremity. The weathered um- bones are perfectly smooth while in variabilis- they always show traces of distantly spaced concentric bands and radial riblets. The Holotype described by Spieker belongs to the Nelson col- lection. According to its figure it is not a normal specimen, the posterior extremity being more rounded than usual. Our knowledge of the external sculpture is based on a well- preserved young shell. It has the frilled lamelle of amathusia but they are more closely spaced than on that species while the intervening spaces are nearly smooth or only feebly waved by the underlying radial shell structure. Both variabilis and angelana are known with certainty only from the Tucillal fossil horizon. Spieker’s records of these species from the Upper Zorritos, based on fragments, in all probability refer to C. spiekeri. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Chione (Chionopsis) spiekeri, n. sp. Plate 3, fig. 6; Plate 12, figs. 4,5 Shell of moderate size or large; in form like Chione gnidia and amathusia, strongly convex with full, prominent umbones and closely adjacent, coiled beaks; posterior extremity more or less pointed with flexuous, umbonal ridge bordered on the anterior side by a wide, shallow sinus; external sculpture similar to amathusia consists of evenly spaced, concentric, frilled lamelle 118 BULLETIN 68 118 and radial riblets; on the umbones and earlier parts of the shell, the radial sculpture consists of primary ribs; these primary ribs become double, later through the introduction of tertiary riblets in the interspaces and the spreading apart of the secondaries (the divided primaries), the whole sculpture on the lower part of the valve consists of numerous, small riblets of the same size throughout; the resulting sculpture is therefore much finer than that of amathusia,; interior concealed. Length, 66 mm.; height, 59 mm.; diameter, 42 mm. Remarks.—Internal casts of this large Chione are quite com- mon in the Miocene rocks of Peru and Ecuador but the external sculpture is seldom preserved. The fragments in the Hopkins collection from localities in the Upper Zorritos of Quebrada Grillo, Toro, etc., and referred by Spieker to variabilis and ange- lana, doubtless belong to this species. Closely related to ama- thusia of the recent West Coast fauna, spiekeri differs by its finer radial riblets and more closely spaced concentric lamellz. Locality and Geologic Occurrence-—Upper Zorritos sand- stones of Que. Picos, Miocene of Sechura (Que. Montera) and along railroad between Amen and Playas, Ecuador. Section LIROPHORA Conrad Chione (Lirophora), sp. Chione (Lirophora) hendersonii Spieker, 1922, Johns Hopkins Univer- sity, Studies in Geology, No. 3, p, 154. (not of Dall, 1903). Several specimens of a Lirophora allied to hendersoni Dall or to paphia Linneaus are in our collection from the Lower Zorritos. They are poorly preserved and those from Zapotal are completely changed to gypsum. They are doubtless the same species which Spieker identified with Chione hendersoni Dall from the Bowden Miocene. Woodring'®® who has studied Spieker’s specimen, re- garded them as distinct, differing from true hendersoni in being larger, less elongate, in having a shallower lunule and crude- er sculpture. Our specimens have about ten concentric lamellar ribs of which the lower five or six are larger and more solid than those of paphia. The upper ribs are usually broken, their base showing simply as widely spaced, thin lamellze. The lamelle are thin-edged over the posterior area, but seem to become strongly 100Woodring, 1925, Carnegie Institution of Washington, No. 366, p. 164, 119 OLSSON: PERUVIAN MtocENE 119 foliaceous at the posterior-ventral extremity. Locahty and Geologic Occurrence.—Lower Zorritos of Zapo- tal and Que. Hiqueron. Chione (Lirophora) grauensis, n. sp. Plate 10, fig: 5 Shell of medium size to large, solid, subtrigonal and of slight convexity ; beaks small, curved forward and situated at the ante- rior one-third; the anterior side somewhat contracted, rounded at end, the posterior side straight along the hinge side, descend- ing, with the posterior extremity subtruncate to broadly rounded ; the ventral side is widely rounded; sculpture consists of irregu- lar, concentric folded ribs, some of which are wide (5.50 mm.) or much narrower (1.50 mm.), somewhat coalescing or separated by wide, channelled grooves ; on the posterior-dorsal ends the ribs become thin and lamelle-like as in pap/ia; in addition the whole surface is overrun with lines of growth; lunule and interior con- cealed. Length, 39.00 mm. ; height, 40.00 mm. ; diameter, 18.00 mm. Remarks.—This species resembles Chione peruviana, a recent species described by Sowerby from Ancon, Peru, but is higher, subtrigonal with flatter and more numerous concentric ribs. Chione (Lirophora) latilirata Conrad, a Chesapeake Miocene species has been recorded by Spieker from the Lower Zorritos of Zapotal, but in absence of figure and specimens this identification is open to question. Locality and Geologic Occurrence.—Cardalitos formation, Up- per Que. Heath. Section CHAMELEA Morch Chione (Chamelea) grzybowski, n. sp. Plate 10 figs. 4, 7 Shell of medium size to large, subcircular, solid, slightly con- vex; ventral margin regularly rounded passing into the more narrowly rounded anterior side; posterior-dorsal side vaulted to slightly convex, ridged with a deep, excavated and flattened escutcheon ; lunule depressed, smooth, elliptical to narrowly cor- date in form and defined by an incised line; surface sculpture is variable, consisting of concentric, flattened folds which are wide 120 : BULLETIN 68 120 on the center and umbos of the valves, much narrower and rib- like on the ventral portion; these folds extend from the lunular side to the dorsal-posterior region becoming slightly narrower on the posterior-dorsal submargins; there are in addition fine lines of growth and where the surface layer has been removed by weathering a fine, internal radial structure is revealed; hinge normal with three cardinal teeth, the anterior right cardinal being large and solid in form. Length, 50.00 mm.; height, 42.00 mm.; diameter, 23.50 mm. Length, 36.00 mm.; height, 33.00 mm.; semidiameter, 9.25 mm. Remarks.—A fairly large, solid species with nearly subcircular outlines and coarse, flattened, concentric sculpture. The con- centric ribs become only a little narrower on the posterior-dorsal submargins and is therefore referred to Chamelea rather than Lirophora. This is possibly the species which Grzybowski identi- fied as Venus munstert @ Orbigny. Locality and Geologic Occurrence.—Cardalitos formation, Up- per Quebrada Heath. Subgenus ANOMALOCARDIA Schumacher Chione (Anomalocardia) anomiana, n. sp. ; Plate 3, fig. 4 Shell small or medium-size, solid, elongate, beaks at the ante- rior one-fourth, the posterior extremity more or less produced, cuneate and flexuous; the sculpture consists of heavy, rounded, concentric folds, approximately two millimeters wide across the middle and separated by wide interspaces ; this sculpture extends from the anterior submargins across the middle of the valves, ending sharply at a shallow, smoothish sinus which extends from the beaks to the posterior-ventral margin so that the valves are distinctly flexuous in this part; surface is otherwise smooth and solid in appearance ; interior unknown. Length, 34.00 mm.; height, 23.50 mm.; semidiameter, 6.5 mm. Remarks.—Our two specimens of this species occur in a hard rock together with Anomua berryi. It is a typical Anomalocardia differing from A. subrugosa Sby. and subimbricata Sby., the two recent West Coast species by its larger shell and heavier, more regular sculpture. The recent species show fine radial lines on the umbones and beak but in the fossil shell although somewhat 121 OLSSON: PERUVIAN MIOCENE 121 encrusted with rock, the umbones appear to have been perfectly smooth. Locality and Geological Occurrence.—Variegated beds, Zorri- tos. Genus TRANSENNELLA Dall Transennella herviderana Spieker Plate 10, fig. 2 Transennella herviderana Spieker, 1922, Johns Hopkins University, Studies in Geology No. 3, p. 143, pl. 9, figs, 1, 2. Original description.—Shell large and heavy for the genus, inflated. Ante- rior dorsal margin concave; posterior dorsal margin nearly straight; ventral margin elliptical. Marginal extremities not known. Umbones full, high, prosogyrate, inclined forward. Surface convex excepting the lunular exca- vation. Sculpture of concentric growth-lines, which are of irregularly spaced folds simulating concentric ribs. Lunule ovate, defined by a slightly impressed line; there is no escutcheon. Hinge normal, the cardinals well developed and distinct in the right valve; in the left valve the anterior lateral tooth is highly developed, taking the shape of a flattened dowel-pin, the flat sides horizontal, the posterior edge straight, and the anterior edge curved, the tooth thus having the shape of a half-D, viewed dorsally. This tooth is received into the usual socket in the right valve. Inner shell un- known. Length (estimated), 25-27; height, 20.5; (semi) diameter, 8 mm. —Spieker, 1922. Remarks.—There are two specimens of a veneroid from the Variegated beds of Quebrada Heath in our collection, which seem to be this species of Spieker. The shell is rather solid, Macrocallista-like in shell structure and sculpture. The surface, lightly weathered, is smooth or marked simply with fine lines of growth. Spieker referred his shells to Transennella principally because of the development of a strong, anterior lateral tooth in the right valve. Our specimens have the hinge and interior concealed and offer no additional evidence as to their generic affinities. The genus Transennella is best distinguished by the tangential sulca- tions of its ventral margin and until specimens showing the valve margins are found, their reference to this genus must remain unsettled. The measurements of our specimen are as follows: Length, 28.00 mm. ; height, 24.00 mm. ; semidiameter, 5.50 mm. Locahty and Geological Occurrence.—Lower Zorritos of Her- videras (Spieker), Zorritos of Que. Cardalitos. 122 BULLETIN 68 122 Superfamily TELLINACEA Family TELLINIDZ Genus TELLINA Linné Subgenus TELLINA, s. s. Section EURYTELLINA Fischer Tellina (Eurytellina) aequicincta Spieker Tellina (Eurytellina) aequicincta Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No, 3, p. 158, pl. 10, fig. 3. Original description.—Shell medium-sized, moderately thick for size, long, of elegant appearance. Anterior margin rounded, produced; ventral margin long and nearly straight. Posterior margin biangular. Umbones pointed, terminal. Surface flattened but convex; a posterior suleus from the beak to the anterior-most marginal angles is the only sharply curved part of the shell. Seulpture of concentric flat-topped ribs with finely graven inter- spaces, about 8 in 5 mm. near the margin, and growing finer towards the beaks. The sculpture is sharply curved at both ends of the shell, and is parallel to the margin, in straight lines over most of its length, Escutcheon long and narrow. Hinge and inner shell not known. Length, 38; height, 22; (semi) diameter, 4 mm.—Spieker, 1922. Remarks.—Our collection contains but a single specimen of this Tellina from the Upper Zorritos sandstones near Punta Picos. The outline of this specimen and its sculpture is quite similar to that of Tellina alternata Say of our Southern States. Spieker considered the Peruvian shell identical with a fragmen- tary Eurytellina from Bowden which Woodring’? does not name. The Bowden shell has more prominent nymphs and doubtless represents a different species. | Locality and Geologic Occurrence.—Zorritos group, Upper Zorritos near Punta Picos; Lower to Upper Zorritos of Que. Heath, Zapotal and las Alturas (Spieker). Tellina (Eurytellina) amenensis, n. sp. Plate 138, figs. 2, 8 Shell of medium size, thin, elongate, flattened to slightly con- vex, elongate-elliptical, inequilateral; beaks small, adjacent, at the posterior one-third ; the anterior side is nearly twice the length of the posterior, the ventral and dorsal margins are nearly paral- lel, the anterior end obliquely rounded on the lower or ventral sides ; posterior side shorter, the dorsal margin straight, descend- ing, the end narrowly rounded; the valves are slightly flexed; sculpture consists of regular, concentric bands or rings which average about one-half millimeters wide on middle of valves, separated by incised or grooved lines; these bands are slightly 101Woodring, 1925, Carnegie Inst. of Washington, Pub. No. 366, p. 168, pl. 28, figs. 8, 9. 123 OLSSON: PERUVIAN MI0cENE 123 waved on their ventral surface so that the shell appears faintly radially striated ; a posterior sulcus extends from the beaks to the posterior-ventral margin; it is finely sculptured with narrow, slightly elevated and waved ridges separated by wider intervals which are the continuation of each alternate, concentric surface ring; escutcheon very narrow, with a large external ligament; left valve a little larger than the right; interior unknown. Length, 40.5 mm.; height, 24 mm.; diameter, 10 mm. Remarks.—Compared with Spieker’s figure of Tellina aequi- cimcta, the outlines of the Ecuadorian shell are found to be high- ~er, the beaks more posterior and the dorsal-posterior margins more arched. The ventral side of the concentric rings are weakly waved so that the sculpture appears faintly rayed. Locality and Geologic Occurrence.—Lower Miocene, railroad cuts between Amen and Playas, Ecuador. Tellina (Eurytellina) cf. felix Hanley Plate 14, fig. 8 ef. Tellina felix Hanley, 1844, Proce. Zool. Soe., p. 71. ef, Tellina felin Hanley, 1846, Thes, Conch. p. 281, pl. 57, fig. 52. Tellina sp. ind. B, Nelson, 1870. Trans. Conn. Acad. Sci., vol. 2, p. 201. Tellina (Angulus) pressa Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 159, pl. 10, fig. 4. (not Dall, 1900). Shell small, thin, compressed, inequilateral; beaks low, near the posterior one-third, the anterior side not quite twice the length of the posterior; dorsal and ventral margin parallel with the anterior side, evenly rounded; posterior portion shorter, some- what contracted, depressed and obliquely subtruncated at its end; surface polished and marked with fine, even, concentric bands on the central and posterior portion but the area immediately ante- rior of the umbonal ridge is smooth; the posterior slope nearly smooth; valves slightly flexed; hinge of right valve with two cardinals, the more posterior one bifid, a large, elongate anterior lateral just in front of the beaks and a small socket-like depres- sion on the posterior-dorsal margin; left valve with a single car- dinal, no anterior lateral and a weak lamella or ridge on the pos- terior margin; muscle scars deep, sometimes with a posterior ray on the thicker shells; pallial sinus not evident. Length, 15.5 mm.; height, 8.75 mm.; diameter, 4.00 mm. Remarks.—A single specimen of this shell was mentioned by 124 BULLETIN 68 124 Nelson at Tellina sp. indet. B. Spieker later considered this shell identical with Tellina (Angulus) pressa Dall, described from the Chipola Miocene. Our collection from Tucillal, contains six specimens of a small Tellina which correspond to the measure- ments and descriptions given by Nelson and Spieker and doubt- less is the same species. They differ by their outlines and sculp- ture from the figures of the holotype of pressa given by Dall and Gardner'’?. The Bowden shell referred to as pressa by Spieker has been named Tellina (Eurytellina) spiekert by Woodring’. It is near the Peruvian form but according to Woodring is said to differ by its more slender nymphs, shorter anterior lateral and stronger sculpture. A recent species dredged at Zorritos but also represented in our collection from the beaches of Boca Pan, Santa Elena and Panama, seems nearly identical with the Peruvian fossils. Both recent and fossil forms have the same outlines and sculptural characteristics. The recent shell is probably the Tellina fehx Hanley, described originally from Panama. The figure given in Sowerby’s Thesaurus shows the posterior side as somewhat shorter than in our specimens. The fossils have a tendency to be somewhat narrower and with a longer posterior side but in other respects they appear too similar to the recent shell to constitute a separate species. Locality and Geologic Occurrence.—Tumbez formation, Que Tucillal. Genus MACOMA Leach Subgenus PSAMMACOMA Dall Macoma (Psammacoma) zapotalensis Spieker Plate 18, figs. 3, 7 Tellina zapotalensis Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 156, pl. 10, figs, 1, 2. Tellina (Angulus?) singewaldi Spieker, 1922, op, cit., p. 161, pl. 10, fig. 5. Shell large, subelliptical or elongate subovate in form, inequi- lateral and slightly flexuous; left valve moderately convex, the beaks at the anterior two-thirds so that the anterior side is near- 102Gardner, 1928, Prof. Paper 142-EH, U. S. Geol. Survey, p. 194, pl. 29, fig. 16. 103Woodring, 1925, Carnegie Inst. of Washington, Pub. No. 366, p. 168, pl. 23, figs. 10. 11. 125 OLSSON: PERUVIAN MIOCENE 125 ly twice as long as the posterior; right valve of less convexity, depressed or slightly flexuous in the posterior region; beaks small, erect and adjacent ; surface smooth or faintly marked with growth-lines ; hinge without laterals, the right valve having two cardinal teeth, the posterior one being strongly bifid and more or less knobbed at the ends; ligament scar external and about 10 millimeters long on a shell about 69 millimeters in length; lunule very small and narrow. Length, 72 mm.; height, 48 mm.; diameter, 17 mm. Length, 65 mm.; height, 45.5 mm.; diameter, 19 mm. Length, 69 mm.; height, 49 mm. ; semidiameter, 9.5 mm. (right valve). Remarks.—Spieker’s description and figures of this species are inaccurate as he had no perfect specimens. The shell which he described as the left valve and of which he figured the inte- rior, seems to be a right valve, judging by the strongly bifid cardinal tooth. The shape of the valves and entire lack of later- als, show this species to belong to Macoma, subgenus Psamma- coma of Dall. The right valve is weakly flexed, being slightly depressed in the posterior region, while the left valve is evenly convex. Young shells are more strongly flexed than adult speci- mens. Macoma zapotalensis is related to Macoma meroénsis Olsson*™ from the Lower Heath shales but is larger, less flexed, less con- vex and with lower, less inflated umbones. Tellina (Angulus?) singewaldi Spieker, described from Zapo- tal, is the young of this species. Small shells of typical zapotalen- sis cannot be distinguished from Spieker’s figure which shows the depressed and flexed right valve. Locality and Geologic Occurrence-—Lower Zorritos of Que. Zapotal. Macoma, sp. Plate 6, fig. 7 It is possible that this shell should be referred to Metis rather than Macoma but the strongly oblique shell, narrow umbones and excavated anterior submargins are characters more common- ly associated with Macoma than Metis. It is represented by two fragmentary right valves, the smaller and more perfect which 104Olsson, 1931, Bulls. Amer. Pal., vol. 17, p. 159, pl. 9, figs. 4, 8. 126 BULLETIN 68 126 is here figured but the material is too poor to serve as type for a new species. The shell is strongly oblique, the anterior and posterior-dorsal margins meeting at the beak to form an angle of about go degrees. The ventral margin is parallel to the anterior-dorsal-margin, the anterior end is broadly rounded. The right valve is strongly flexed by a wide, depressed zone extending from the beaks across the posterior-ventral part of the valves. The posterior area is convex and of medium width as in the more strongly flexed species as Macoma constricta Bruguiere. Length, 40 mm.; height, 36 mm.; diameter, 8.5 mm. Length, 28 mm.; height, 26 mm.; diameter, 6 mm. Locality and Geologic Occurrence.—-Variegated beds, Boca Pan. Metis, sp. An internal cast of the left valve and several shell fragments of a large Metis were found at Tucillal. The cast shows a shell, rectangular in form, the beaks nearly central and a broad poste- rior flexure about one-third of the shell in width. It seems close- related to Metis excavata Sowerby of the recent West Coast fauna. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Family SEMELIDA Genus SEMELE Schumacher Semele laevis costaricensis Olsson Semele laevis Sowerby, var. costaricensis Olsson, 1922, Bulls. Amer. Pal., vol. 9, p. 430, pl. 29, fig. 1. Semele laevis costaricensis H. K, Hodson, 1931, Bulls, Amer. Pal., vol. IGS 495 ale, jolls Gh, es O, For original description see vol. 9, p. 430. Casts and badly weathered specimens of a Semele allied to S. levis Sowerby of the recent Panama fauna, occur in the collections from Zorritos. By its broadly rounded posterior ex- tremity, this shell seems nearer the subspecies costaricensis de- scribed from the Caribbean Miocene of northern Costa Rica than to typical levis. 127 Ousson: PERUVIAN MIocENE 127 A specimen of a very large Semele was found at Tucillal. The height of the shell is about 90 millimeters. It is subcircular to broadly elliptical in form with high erect beaks and depressed shell. It may be compared to flavencens Gould but is much larger than any recent species which I have seen. -Family DONACIDZE Genus IPHIGENIA Schumacher Iphigenia peruviana, n. sp. Plate 13, fig. 5 Shell small, subinflated, donaciform; umbones wide, with the small beaks slightly posterior to the middle; posterior side short- er, subtruncate, its dorsal margin slightly convex, ending in a blunt point at the posterior extremity; anterior side, somewhat longer, the dorsal margin nearly parallel with the posterior half of the ventral margin; the anterior extremity obliquely rounded ; surface smooth, showing the growth-lines which are grouped together in wide bands which may correspond to stages of growth; no radial sculpture except very faint, irregular streaks near ventral margin; hinge typical, the right valve with two cardinals, the posterior being strongly bifid and an anterior later- al; ligament external, seated on a nymph just back of the poste- rior cardinal ; pallial sinus deep but detail not clearly marked in the holotype; ventral margin smooth. Length, 30.5 mm.; height, 17.5 mm.; semidiameter, 5 mm. Remarks.—Externally, this shell bears a likeness to Donaz, its ventral margin being quite straight while in the two recent American species, /. brasiliana Lamarck and J. altior Sowerby, the ventral margin is quite flexuous with a well-marked sinus lying just in front of the posterior ridge. The smooth surface, entire absence of radial shell structure and the hinge show that this species is a true /phigenia. Mrs. Hodson? has recently described /. olssoni from Vene- zuela. This species is related to the Atlantic brasiliana and is distinguished from peruviana by its larger size and typical /phi- genia-like form. Locahty and Geologic Occurrence.—Zorritos formation, Que. CGharank Stas 10: 105H, K, Hodson, 1931, Bulls. Amer. Pal., vol. 16, p. 19, pl. 4, figs. 2, 38, 6. 128 BULLETIN 68 128 Superfamily MACTRACEA Family MACTRIDAX Genus MACTRA Linné Subgenus MACTROTOMA Dall Section MICROMACTRA Dall Mactra (Mactrotoma) iridia.n. sp. Plate 14, fig. 5 Shell small, thin, oblong-ovate, subequilateral, slightly convex ; posterior-dorsal area of moderate width, flattened to slightly vaulted, smooth and limited by an angled ridge; it also has a faint ridge or groove extending from the beaks about one-third the distance from the umbonal angle to the dorsal margin; um- bones nearly central with small, forward inclined beaks ; anterior and posterior-dorsal side nearly straight, descending, the ante- rior and posterior ends of nearly equal size and form; ventral margin straight to slightly rounded; the umbones are faintly sulcated over a space of about 15 millimeters, the rest of the shell being smooth except for growth-lines; interior unknown. Length, 45 mm.; height, 32, mm.; semidiameter, 8.25 mm. Remarks.—This species has the form of a small Mactrella alata except that the valves are more equilateral with less promi- nent but wider umbones. The umbones and beaks are faintly sulcated as typical of the section Micromactra. From the two re- cent West Coast species, namely californica Conrad and angusta Deshayes, iridia differs by its higher and larger shell. Mactra (Mactrotoma) macescens Guppy from Manzanilla, Trinidad, has stronger umbonal sulcations, those along the anterior or lunular side extending almost to the ventral margin. Associated with iridia, is a smaller Micromactra with more strongly sulcated beaks. They may be the young of iridia but probably represent another species allied to californica Conrad. Our material of this species, consisting entirely of casts, is too fragmentary for more detailed characterization. Locality and Geologic Occurrence.—Lower Miocene, Railroad cuts between Amen and Playas, Ecuador. 129 OLSSON: PERUVIAN MI0ocENE 129 Subgenus MACTRELLA Gray Mactra (Mactrella) exoleta Gray Mactra exoleta Gray, 1837, Mag. Nat. Hist., p. 372. GS «¢ Reeve, 1854, Conch. Icon., Mactra fig. 16. ae ee Packard, 1916, Univ. of California, Bulls, Dept. Geol- ogy., vol, 9, p. 281, pl. 12, figs. 4a, 4b; pl. 13, fig. 2. os «¢ Olsson, 1922, Bulls. Amer. Pal., vol. 9, p. 434, pl. 28, fig. 2. Remarks.—Mactrella exoleta Gray is a recent species of the Panama fauna ranging from the Gulf of California southward to northern Peru, its most southerly known occurrence being at Punta Picos. It is distinguished from Mactrella alata Spengler and clisea Dall by the non-alation of its umbonal angle. The fossil specimens from the Peruvian Miocene are internal casts from the Upper Zorritos sandstones. They are often dis- torted, due to crushing, so they vary from forms nearly as high as long to others nearly twice as long as high. Small patches of the thin shell are preserved on some examples. Mactrella exoleta has been found as fossil in the Miocene of northern Costa Rica and Arnold and Packard have recorded it from the Pleistocene of California. Locality and Geologic Occurrence.—Upper Zorritos of Punta Picos. Harvella elegans tucilla, n. subsp. Plate 14, fig. 1 Two specimens of a large Harvella were collected at Tucillal. The posterior-dorsal area has been destroyed on both specimens, only a short space just posterior to the beak on the right valve of the larger specimen has a section of the sharp, posterior carina and deep escutcheon still preserved. } The larger specimen has a height of 78 millimeters while re- cent specimens of Harvella elegans from Peru and Ecuador do not exceed 60 millimeters in height. The fossil shell also seems to be higher with fine, more regular sculpture and with a porpor- tionately shorter lunular edge. The lunule is defined by an im- pressed line which, however, extends but half the distance from the beaks to the ventral margin. Recent specimens of Harvella elegans do not seem to have the lunule defined by an impressed line although often a colored ray is present. The much larger size of the Tucillal fossil and their somewhat different sculpture 130 BULLETIN 68 130 and form entitle them to subspecific recognition. Havella elegans occurs in the Miocene of Colombia as record- ed by Anderson***. Colombian specimens in our collection seem to be identical with the recent species. A small species similar to elegans has been described by Maury’*’ from the Manzanilla beds of Trinidad as Harvella sanct-blasu. The living shell from Panama Bay has recently been redescribed by Lit as Reta maxima. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Genus MULINIA Gray Mulinia zorritensis Nelson Plate 14, fig. 6 Mactra zorritensis Nelson, 1870, Trans. Conn. Acad. Sci., vol, 2, p. 201. Mactra, sp. ind. Nelson, 1870, op. cit., p, 201. Mulinia zorritensis Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 165, pl. 10, figs. 8, 9. Original description.—Shell small, very delicate, inflated, triangular. Anterior margin nearly straight dorsally, curving into the ventral margin, which is elliptical; posterior margin nearly straight, meeting the ventral margin in a sharp angle. Umbones subcentral in position, apically small, inflated, prosogyrate, about 1.25 mm. distant in a shell 22 mm. long by 19.5 mm, high. Anterior surface evenly convex; medium surface longitudi- nally flat and vertically convex. A sharp posterior carina is distinct from the top of the beak to the posterior marginal angle; behind it the surface is flat ventrally and slightly excavated near the beaks. Sculpiure of fine concentric lines; in some shells irregular differentiation of growth-stages gives a somewhat rough appearance, and others are more nearly smooth. Dorsal areas distinct, delimited by sharp lines which form a lanceolate posterior area and an olive-shaped anterior area; surface of areas finely striate longitudinally. Hinge normal, very delicate. Dimensions of 2 speeimens: Length, 19.5; height, 16; diameter, 11 mm. Length, 22; height, 19.5; diameter, 9.5 mm.—Spieker, 1922. Remarks.—Nelson’s original description being very meager, I have copied Spieker’s fuller description of the same speci- mens. Nelson differentiated two species among the .Mulinias in his collection, the name zorritensis being given to the higher forms, the other being left undesignated. As Spieker has pointed out, the range of variation amongst these shells, as is true with many species of this genus, is too great to permit their separa- tion into more than one species. Mulimia zorritensis resembles 106Anderson, 1929, Proc. Calif. Acad. Sci. 4th series, vol. 18, p. 176, pl. 21, Mey 188, Bulls. Amer. Pal., vol. 10, p. 266, pl. 21, fig. 2. 108Chih Chang Li, 1930, Bull. Geol. Soc. China, vol. 9, p. 263, pl. 5, fig. 35: see also Pilsbry, 1931, Proc, Acad. Nat. Sci. Phila., vol. 83, p. 481. 131 OLSSON: PERUVIAN MI0cENE = alan Mulimia lateralis Say of the East Coast, but is usually higher and more fragile. The recent West Coast Mulinias are larger. Locality and Geologic Occurrence—Tumbez formation, Que. Tucillal. Genus LABIOSA (Schmidt) Mo6ller Subgenus RAETA Gray Labiosa (Raéta) undulata undulata Gould Plate 14, fig. 11 Lutraria undulata Gould, 1851, Proc. Boston Soe. Nat. Hist., vol. 4, 89. Journ, vol, 6, pl. 15, fig. 7. Labiosa undulata Stearns, 1894, Proc. U. S. Nat. Mus., vol. 17. p. 157. a Lamy, 1909, ‘Jour. de conchyliologie, vol. 57, p. 249. Labiosa (Raéta) wndulata Lamy, 1917, Jour. de conchyliologie, vol. 63, pp. 355, 356. os os oe Olsson, 1924, The Nautilus, vol. 37, p. 130. ve ve e H. K. Hodson, 1931, Bulls. Amer. Pal., vol. 16, p. 21, pl. 7, fig. 6. Raéta gibbosa Gabb, 1870, Am. Jour. Conch., vol. 5, p. 30; Gabb, 1874, Jour. Acad. Nat. Sci. Philadelphia, vol. 8, p. 264, pl. 35, figs. 8, 8a, pe re Steinmann, 1929, Geologie von Peru, p. 257, fig. 261. Labiosa (Raeta) gibbosa Anderson, 1929, Proc. Calif. Acad. Sci., 4th series, vol. 18, p. 177. Labiosa (Raéta) ventricosa Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 169, pl. 10, fig. 11. Labiosa (Raéta) hasletti Anderson, 1929, Baw. Calif. Acad, Sei., 4th series, vol. 18, p. 177, pl. 23, figs. 2,3 Anatina undulata Dall, 1921, Bull. ‘112, U. S. Nat. Mus., p. 51. Original description.—T. oamidida papyracea, ovata, posticé hians, nisi propé marginem posticum concentricé undata, concinné rugosa; apicibus vix anticis; latere antico rotundato; latere postico angustato, compresso, ad apicem rotundato, margine dorsali declivo, rectiusculo, costa submarginali munito. Long., 2%; alt., 2; lat., 1% poll—Gould, 1851. Remarks.—Gould’s Lutraria undulata was originally described from Lower California. Gould’s figure was drawn from a young specimen about 214 inches long with strong, regular con- centric sculpture over the whole shell. It has been recorded as a rare species at San Diego by Cooper, and by Gould, Stearns and Lamy from Lower California. Dall in his checklist of the Marine Mollusks of the North West Coast gives its range south to Panama. The Panama record has not been verified and may be based on Carpenter’s’®® comparison of Lutraria elegans (Har- vella elegans) from the Adams collection with Raéta canaliculata. 109Carpenter, 18638, Proc. Zool. Soe., p. 868 (80); reprinted 1872, Smith. Mise. Coll., No. 252, p. 204. 132 | BULLETIN 68 132 The species is, however, quite common locally in northern Peru, particularly near Piedra Redonda but extending north in di- minishing numbers past Tumbez and along the west coast of Ecuador. Its apparent absence elsewhere in the Panama province is probably due to the lack of sufficiently extensive collecting or the species may have retired to the cooler, deeper waters off- shore. Several other species first described from Lower Califor- nia and unknown in the more tropical portions of the Panama province, occur in abundance in northern Peru and western Ecuador, such as Mactrinula californica Conrad and Cryptomya californica Conrad. Dall and Carpenter’? refer to undulata as the Pacific analogue of East Coast R. canaliculata Say. Actually the two species are very distinct and belong to two separate groups with different geologic history. R. undulata is usually a larger, more convex shell with full umbones and nearly central beaks. The umbones and middle of the shellare usually distinct- ly rayed. The external sculpture is very variable and may con- sist of strong, regular, wave-like undulations or they may become irregular, merging with crowded growth-lines near the ventral margins. R. canaliculata has not been found as fossil in beds older than the Pleistocene, the Chesapeake Miocene species being the rare R. alta Conrad, first described from North Carolina but also known from Yorktown. Miocene Raétas from the West Indian and Caribbean region as well as from Peru, belong to the group of undulata. As recently shown by Mrs. Hodson, Miocene speci- mens of Raéta from Venezuela cannot be separated from recent undulata. The Lower Miocene form is usually smaller and cor- responds to Spieker’s gardnere. A still smaller variety, named mirandana by Mrs. Hodson is recorded from the Venezuelan Middle and Upper Oligocene, thus extending the range of Raéta for the first time below the Miocene. Anderson’s Labiosa (Raéta) hasletti from the Upper Tubara Miocene of Colombia judging by specimens in our collection from the type locality, cannot be distinguished from gerontic examples of undulata from the Peruvian beach. Pilsbry and Johnson’s Labiosa gabbi is probably but a variety of undulata from the Santo Domingan 110Carpenter, 1864, Report of the British Association for the Advance- ment of Science for 1863, p. 681; reprinted 1872, Smith. Misc. Coll., No. 252, p. 167. ew 133 OLSSON: PERUVIAN MIOCENE 13 Miocene. Gabb’s Raéta gibbosa was described in 1870 apparently from the tablazo beds above Paita and therefore a late Pliocene or early Pleistocene fossil. I was unable to locate the type speci- men at the Philadelphia Academy but there is little doubt that it is the same as undulata. Dickerson’s''' records of gibbosa from Lower California, have been considered as R. gardnere by Woodring*”. Two specimens of Raéta undulata were collected in the Tum- bez beds of Quebrada Tucillal at Zorritos. One specimen very badly crushed, has an estimated length of about 180 millimeters, larger than any recent specimen of undulata which I have seen. The second specimen is quite normal and is here figured. Spiek- er’s Raéta ventricosa described from the Nelson collection, is doubtless merely a broken undulata. The extreme anterior beak with the dorsal margin extending across the growth-lines and sculpture at right angles, show that the shell is not perfect but owes its peculiar form to having lost a large part of the poste- rior-dorsal submargins. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Labiosa (Raéta) undulata gardnerae Spieker Plate 14, fig. 4 Labiosa (Raéta) gardnere Spieker, 1922, Johns Hopkins University, ' Studies in Geology, No, 3, p. 168, pl. 10, fig. 10. Labiosa (Raéta) gardnere Anderson, 1929, Proe. Calif. Acad. Sei., 4th series, vol. 18, p. 177. Labiosa undulata gardnere H. K. Hodson, 1931, Bulls. Amer. Pal., vol. 16, p. 21, pl. 7, fig. 5. Labiosa gibbosa Dickerson, 1917, Proe. Calif. Acad. Sei., 4th series, vol. 7, p. 202. (aced. to Woodring, 1928, Bowden gasteropods, p- 95). Original description.—Shell small, anteriorly inflated, very thin, subtri- gonal in outline. Anterior margin broadly rounded; ventral margin ellipti- eal, ascending rather sharply to the posterior marginal angle Which is less than a right angle; posterior-dorsal margin nearly straight. Umbones small, inflated, pointed, inclined slightly backward, prosogyrate, Anterior surface highly convex, with a suggestion of a carima. Posterior surface attenuate, flattened, with a slightly broad concavity halfway between the beaks and the marginal angle. Sculpture of concentric plications, externally sharp at the top and with concave slopes, about equal in declivity dorsally 111Dickerson, 1917, Ancient Panama canals, Proc. Calif. Acad. Sci., 4th series, vol. 7, p. 202. series, vol. 7, p. 202. 112Woodring, 1928, Miocene Mollusks from Bowden, Jamaica, Pt. 2, Car- negie Institution of Washington, No. 385, p. 95. 134 BULLETIN 68 134 and ventrally; interspaces comparatively broad, U-shaped. Hinge not Seer Length, 28.5; height, 23.5; (semi) diam., about 8 mm.—Spieker, Remarks.—The Lower Miocene Raeétas from the Zorritos formation differ from typical undulata principally by their smaller size and consequently thinner shell and finer sculpture. The largest specimen in our collection has a length of about 45 millimeters. The shells are usually crushed and distorted so that specific differences based on form alone are very uncertain. Spieker’s Fk. gabbi is probably a flattened, elongated gardanere. Kength, 42mm; height, 35 mm,; semidiameter, 10:5) mm: Length, 43 mm.; height, 25 mm. (imperf.) ; semidiameter, 7 mm. Locality and Geologic Occurrence.—-Zorritos formation, Vari- gated, Punta Picos; Upper Zorritos, P. Picos, Que. de los Alturas (Spieker). Superfamily MYACEA Family CORBULIDZ Genus CORBULA Bruguieére The selection of different species of Corbula by conchologists at the type of this genus has resulted in considerable confusion regarding the classification of these abundant recent and Tertiary shells. Gardner'’® in her study of this group, particularly as it affected the classification of the Lower Miocene species of Florida, accepted Children’s designation of C. nucleus Lamarck (C. gibba Olivi) as the type of true Corbula. More recently Stewart’ has found that the first type designation of Corbula is that of Schmitt, who selected C. sulcata Lamarck. This is the usage followed by most conchologists with the exception of Dall*'’, who, through a process of elimination, regarded C. gal- lica Lamarck as the type species and which is also the type of Fischer’s Bicorbula. Typical Corbula, type C. sulcata is possibly not represented in the American Tertiary and recent faunas unless C. gatunensis 113Gardner, 1928, Prof. Paper 142-E, U. S. Geol. Survey, pp. 226-228. Nauti- lus, 1926, vol. 40, p. 48. 114Stewart, 1930, Acad. Nat. Sci. Phila., Special Publication No. 8, pp. 286, 287. 115Dall, 1898, Trans. Wagner Free Hgsticuce: vol. 3, pt. 4, p. 887, 135 OuLsson: PERUVIAN MI0cENE 13 or Toula from the Miocene of Panama may prove to belong here. A ~ possible synomym of true Corbula is Notocorbula Iredale’ based on C. vicaria Iredale from Australia. C. sulcata is a large, coarse species, inequivalve, the right valve being much larger and considerably overlapping the left. The umbones are capped by the conspicuous nepionic shell which differs from the adult somewhat in sculpture while the smaller left valve is often nearly smooth as described and figured by Reeve. The adult sculpture is coarse, consisting of strong, concentric rib-like undulations. The posterior keel is sharp. The small Corbule with unequal and discreptantly sculptured valves such as vieta Guppy and heterogenea Guppy, in Gardner’s classification would be referred to true Corbula. Dall included these species in Aloidis Muhlfedt which having C. sulcata as its type is a direct synomym of Corbula, s. s. Cossmann and other European writers have placed these shells in Agina Turton which is believed to be a Saxicava. This group is evidently in need of a name but until the involved synomym of Corbula is better known, it is best to leave them undesignated. The group is repre- sented in the Peruvian Miocene by two «species, C. bradleyi Nelson and prenuncia Spieker. Caryocorbula Gardner, 1926, type C. alabamensis Lea. This subgenus was proposed by Gardner for the elongate, rostrate, subequivalve species commonly referred by American concholo- gists, following Dall’s usage, to Cuneocorbula Cossmann. Cuneo- corbula as exemplified by its type species C. biangulata Deshayes from the Parisian Eocene is apparently unknown in America. Caryocorbula includes many of the commonest species in the American fauna and in the Peruvian Miocene is represented by the following species: C. fabiformis Spieker, propinqua Spieker, bravoana Spieker, nelsoni, n. sp. and ovulata Sowerby. The subgenus Bothrocorbula Gabb, is monotypic with C. viminea Guppy from the Miocene of Jamaica and Costa Rica as type. It is a solid shell with subequal, coarsely sculptured valves and especially characterized by a deep lunular pit. Besides the type, three other species have been referred to Bothrocorbula, C. synarmostes Dall and radiatula Dall from the Chipola Miocene 116Iredale, 1930, Records of the Australian Museum, vol. 17, p. 404, 136 BULLETIN 68 136 and C. wilcoxi Dall from the Caloosahatchie beds of Florida. In - synarmostes the lunule is very small, somewhat larger in radia- tula and quite as deep in wilcoxi as in viminea. C. hexacyma Brown and Pilsbry from Gatun, C. buenavistana F. Hodson from Venezuela and C. cruziana, n. sp. from Peru, closely resemble viminea in external characters but have no lunule. These species are obviously more closely related to Bothrocorbula than to Caryocorbula and bear much the same relationship to Bothro- corbula as Lucina, s. s. does to its subgenus Here. The section Hexacorbula with C. hexacyma Brown and Pilsbry as type is here proposed for these species. The subgenus Tenwicorbula, genotype C. tenuis Sby,. of the - recent Panama fauna, is proposed for a group of thin-shelled Corbulas from the Peruvian Miocene and recent fauna. The shells are thin, delicate, subequivalve, rostrate or bicarinate, the posterior side varying considerable in length with a strong, cari- nate, posterior keel, the posterior area more strongly sculptured with a well-defined, smoothish, elliptical, escutcheon-like area extending behind and somewhat beneath the beaks. Three species or subspecies of this subgenus occur in the Peruvian Miocene: C. tenuis lupina, n. subsp., acutirostra Spieker and zorritensis, n. subsp. C. tenwis is a member of the recent Panama fauna and has been dredged at Zorritos. Corbhulal = ) prenuncia Spieker Corbula (Aloidis) prenuncia Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 172, pl. 10, fig. 12. Original description.—Shell small, inflated, triangular. General form pyramidal; anterior margin short, rounded; ventral margin elliptical; posterior margin biangular, very little produced. Umbone of right valve high, prominent, strongly incurved, inflated. General surface smoothly rounded; rostrum keels well marked, but postericr portion not markedly gibbous. Sculpture of heavy, proportionally coarse, concentric lire, about 18-20 on the right valve. Inner shell and left valve unknown. Length, 5.5; height, 5.5 mm.—Spieker, 1922. Remarks.—This species is not represented in our collection. It is known only from the right valve. Locality and Geologic Occurrence.—Lower Zorritos, north of Quebrada Boca Pan (Spieker). 137 OLSSON: PERUVIAN MIOCENE 1; Q Corbula (_____.._) bradleyi Nelson Corbula bradleyi Nelson, 1870, Trans. Conn. Aead, Sei., vol. 2, p. 200. Corbula (Aloidis) bradleyi Spieker, 1922, Joins Hopkins University, Studies in Geology, No. 3, p, 171, pl. 10, figs, 13, 14. Original description.—Shell very ventricose; wedge-shaped, umbones large, convex, ineurved over the hinge area. An.erior margin rounded; lunule very deeply impressed; ligament area twice tie length of the lunule; strongly angulated with the posterior margin. Hinge tootn large, recurved; fossette triangular and deeply impressed. Surface of shell marked by strong, convex, concentric lines, separated by narrow but well marked spaces, about five of the lines in five millimeters. The triangular shape is very characteristic, as is also the angulation of the posterior margin; beak very prominent.—WNelson, 1870, The posterior surface is marked by two carinas about 5 mm. apart at the hinge, between which the surface is flat to somewnat excavated. The strong lire curve across this surface, diminishing in size as they converge across the impressed area which Nelson has incorrectly described as an escutcheon. The liration tends to be irregular ventrally. Length, 20; height, 18.5 mm.—Spieker, 1922. Remarks.—This species was not rediscovered at Tucillal and I can add nothing to Nelson’s and Spieker’s description of the form. Locality and Geologic Occurrence——Tumbez formation, Tucillal. Subgenus CARYOCORBULA Gardner -Corbula (Caryocorbula) bravoana Spieker Corbula (Cuneocorbula) bravoana Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 174, pl. 10, fig. 17. Original description—sShell of good size, distinetly triangular, less rounded than the usual Cuneocorbulas. Anterior margin straight dorsally, somewhat abruptly curved below. Ventral margin nearly straight, ascend- ing slightly throughout its length; posterior-dorsal margin straight in left valve, biangular in right. Umbones anterior, not prominent, sharp, slightly prosogyrate. Anterior surface rounded. Surface bounded by anterior mar- gins, first posterior carina, and ventral margin forms a triangle, subeyelindi- eal in contour. First posterior carina prominent, bevelled in both valves, curved upward ventrally and leading into the umbo in a straight line in the left valve, curving over slightly in the right valve on account of its convex- ity. Second posterior carina not prominent; clearer in right valve than in left. Interearinal space concave in both valves, larger in right. Sculpture ot raised concentric ridges, whose sharper slope is above, about 11 in the space of 5 mm. on the right valve and 16 in the same space on the left. The sculpture is of constant strength over the entire shell. Neither lunule nor escutcheon is apparent. Interior of shell unknown. The shell is of greatesi diameter at the prominent carina. Length, 11.5; height, 7.5; diameter, 4.5 mm.—Spieker, 1922, Remarks.—tThis is a small Corbula described from the Lower Zorritos. The valves are nearly equal, the right one being slightly 138 BULLETIN 68 138 larger, its margin slightly overlapping the left along the posterior and ventral sides. Beaks central, the anterior side well rounded, the posterior cuneate or pointed. The posterior keel is not strong. The surface sculpture is rather coarse, consisting of even, con- centric ribs, somewhat weaker on the left valve. No lunule or escutcheon. C. propinqua Spieker described from the Variegated beds of Oue. Tucillal seems close to bravoana but is much larger. As figured, the posterior end is as strongly pointed in propinqua as in bravoana. | Locality and Geologic Occurrence.—Lower Zorritos, between Quebradas Heath and Charan (Spieker), Zapotal. Corbula (Caryocorbula) fabiformis Spieker Corbula (Cuneocorbula) fabiformis Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 172, pl. 10, fig. 15. Original description.—Shell of average size, ovate, somewhat produced. Anterior margin rounded, ventral margin elliptical; posterior margin short and biangulate. Umbones anterior, not prominent. Sculpture of fine, con- centric lines. Surface ovately convex, the rostral portion flat, with the rostral keel obsolescent, and the intercarinal surface coneave. Cardinal angle not acute. Posterior and [end] pointed, although somewhat bluntly so. Lunule and eseutcheon absent, Pallial line impressed. Teeth unknown. Length, 9.5; height, 6; (semi) diameter, 2.5 mm. (right valve); diameter of entire shell, 4.5 mm.—Spieker, 1922, Remarks.—tThis species is not in our collection. Corbula (Caryocorbula) propinqua Spieker Corbula (Cunéocorbula) propinqua Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 174, pl. 10, fig. 16. Original description.—Shell ovate, somewhat produced, of good size for the section. Anterior margin somewhat produced, rounded; ventral mar- gin elliptical, ascending posteriorly; posterior (dorsal) margin nearly straight. Shell pointed posteriorly. Umbones inconspicuous, anterior in position. General surface convex except posteriorly, where a narrow concave area exists between the characteristic keel. The ventral surface of the left valve is squared off, The extreme posterior portion of the left valve (and possibly the right—specimens broken) is drawn out to form a horizontal chisel-like point inside the end of the rostral keel. Sculpture of fairly regular, fine concentric ribs which are slightly more prominent and more irregular on the right valve. On the chisel-like point the sculpture is of fine longitudinal lines. No lunule, and small trace, if any, of an escutcheon is visible on the material examined. Length, 15; height, 9; diameter, 5,5 mm. —Spieker, 1922. Remarks.—Spieker’s figure of a left valve of propinqua re- sembles bravoana but it is a larger species and belongs to a 139 OLSSON: PERUVIAN MIOCENE 139 higher horzion. The two forms are very close and possibly rep- resent the same species but in the absence of specimens, this question must remain for other workers to decide. Locality and Geologic Occurrence.—Variegated beds of Que. Tucillal. Corbula (Caryocorbula) nelsoni, n. sp. Plate 14, figs. 2, 9 Shell of medium size, convex, rather solid, the right valve a little larger than the left and overlapping it along the ventral margin; outline of the shell is subelongated, somewhat distorted in appearance, the posterior end being a little produced and flex- uous; when adult the ventral part of the right valve becomes smoothly reflected thus greatly increasing the convexity of the shell; beaks central, very slightly prosogyrate, the umbones wide, sometimes with a shallow sinus extending across it to the ventral margin; no lunule; a weak posterior keel defining a narrowly elliptical posterior area; the posterior extremity is longer in the right valve than in the left, rostrate; sculpture consists of con- centric threads separated by deep grooves which are fine and even on the nepionic part of the valves and irregular on the re- flected part of the right valve; the nepionic shell particularly on the right valve is delicately marked with fine, thread-like radials ; hinge normal; cavity of valves deep. Length, 16.00 mm.; height, 10.75 mm.; diameter, 9.00 mm. Length, 17.50 mm.; height, 11.00 mm.; semidiameter, 6.00 mm. Remarks.—Corbula nelsom is related to C. nasuta Sby, of the recent Panama fauna. The fossils differ from the recent species in their average larger size, coarser and heavier shell and by their shorter, less rostrated posterior extremity. Both species show fine, thread-like radials on their umbonal or ne- pionic valves. Corbula nasuta Sby. has been recorded from Panama and Jipijapa, Ecuador, and it was dredged in considerable numbers at Zorritos. Locality and Geologic Occurrence.—Tumbez formation, Tucil- lal. 140 BULLETIN 68 140 Corbula (Caryocorbula) ovulata Sowerby Corbula ovulata Sowerby, 1833, Proce. Zool. Soe., p. 35. os a Reeve, 1844, Conch. Icon. Corbula, pl. 1, fig. 7 Corbula ovulata Sowerby is a recent species ranging from Panama southward to northern Peru, its most southerly known occurrence being at Punta Picos and Zorritos. The species shows considerable variation from elongate, thin-shelled forms which have lived in deep, quiet waters to coarse, thick-shelled types of the open beach and rocks. A single right valve was found at Tucillal associated with Corbula nelsom. It is a solid, elongate shell with strong sculp- ture on the anterior submargins fading away on the posterior side. It cannot be separated even varietally from recent examples of ovulata. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Subgenus BOTHROCORBULA Gabb Section HEXACORBULA, n. sect. Type.—Corbula hexacyma Brown and Pilsbry The following is a description of the section Hexacorbula: Shell moderately large and heavy, subequivalve to slightly in- equivalve, the ventral margin more or less reflected on both valves; posterior keel simple, nearly the same on each valve, pointed to slightly rostrated at its end; sculpture of coarse con- centric, wave-like ribs; no lunule or escutcheon. Remarks.—The subgenus Bothrocorbula, type C. viminea Guppy is distinguished by its deep lunular pit. Three other Cor- bulas have been referred to Bothrocorbula. In C. synarmostes Dall from the Chipola Miocene, the lunule is very small and easily overlooked, it is much larger in radiatula Dall, also from the Chipola Miocene and quite as deep in wilcoxi Dall, from the Florida Pliocene as in viminea. All the species have a similarly coarse, heavy shell with strong, wave-like concentric ribs. Cor- bula hexacyma Brown and Pilsbry from Gatun, the recently de- scribed C. buenavistana F. Hodson from Venezuela and the new 141 OLSSON: PERUVIAN MIocENE 141 species described here as cruziana resemble viminea in their sculpture and heavy shell. Although these species have no lunule, they appear more closely related to viminea than to Caryocorbula where they otherwise would be placed. Corbula (Hexacorbula) cruziana, n. sp. Plate 3, fig. 5; Plate 4, fig. 9 Shell of medium size, solid, depressed; outline of valves is elongated, subtrigonal, the length about twice the height; beaks erect, pointed, the umbones with a slight sinus across the middle ; the ventral margin is strongly reflected, forming a narrow, flat- tened, ventral border; the major part of the surface of the valves is flattened or only slightly convex, the depth of the valves is principally due to the contracted ventral margin; anterior side somewhat contracted, rounded at end; posterior side of much the same shape with a strong, sharp posterior keel forming an ob- liquely truncated, chisel-like outline at its end; sculpture similar on both valves and consists of large, strong, rib-like concentric folds separated by deep intervals; on a valve of an average size, there are about eight of these concentric ribs; no lunule nor escutcheon; shell very solid so that the interior of the shell shows a rounded deep body-cavity and distinct and somewhat impressed muscle scars; hinge normal. Length, 16.00 mm.; height, 10.00 mm.; semidiameter, 5.00 mm. (left valve). Length, 17.00 mm.; height, 10.50 mm.; semi- diameter, 8.50 mm. Remarks.—This species is similar in its sculpture to C. hesxa- cyma Brown and Pilsbry from Gatun but differs by its smaller shell and more strongly contracted, flattened ventral border of its valves. It seems to be restricted to the Lower Zorritos. Locality and Geologic Occurrence.—Lower Zorritos of Zapo- tal and Quebrada La Cruz. Subgenus TENUICORBULA, n. subg. Type.—Corbula tenuis Sowerby The following is a description of the subgenus Tenuicorbula: Shell usually thin, inequilateral, subequivalve; posterior side contracted, with a strong, cord-like posterior keel, defining the posterior area which is more coarsely sculptured than the rest 142 BULLETIN 68 142 of the valve surface; a smaller secondary keel in the middle, defines an escutcheon-like area; no lunule; posterior side oblique- ly truncate and bicarinate at the end; hinge normal with a strong cardinal tooth in right valve, the ligament pit notch-like, small and seemingly passing internally beneath the beaks; in the left valve, a grooved posterior cardinal; external sculpture of fine, concentric threads coarser on the posterior area. Remarks.—In Corbula tenuis Sowerby, the shell is unusually thin for a species of this genus. The posterior side is contracted and with a strong, cord-like keel defining the posterior area and with a smaller, secondary keel in the middle. The posterior ex- tremity is obliquely truncated and biangular in outline. An escut- cheon-like area is clearly defined by the secondary keel and smoother in its surface markings. The surface sculpture consists of concentric threads considerable coarser on the posterior area. Corbula tenuis 1s very rare in collections. It was originally described by Sowerby from a single specimen dredged by Cum- ings in 12 fathoms of water at Montijo Bay, Panama. A single valve was collected by C. B. Adams at Panama while the New- comb collection at Cornell has a single valve from Mazatlan. We were fortunate in dredging several specimens at Zorritos and a few beach specimens were found near Puerto Pizarro. The species has recently been redescribed by Chih Chang Lit” from spcimens brought up by channel dredging in Panama Bay as Corbula glypta. A variety of Corbula tenuis is found fossil in the Upper Mio- cene beds of Quebrada Tucillal. Corbula acutirostra Spieker and its variety zorritensis belong to Tenuicorbula. Corbula bicarinata Sowerby, a recent Panamic species should probably be placed in this subgenus although the shell is quite heavy. Another re- cent species belonging to Tenuwicorbula is Corbula aequivalvis Philippi (C. cubaniana D’Orbigny) of the West Indian fauna. In this species the secondary keel and escutcheon-like area is small but otherwise quite typical. 117Chih Chang Li, 1930, Bull. Geol. Soc. of China, vol. 9, no. 3, p. 263, pl. 5, figs. 38, 38a. See also Pilsbry, 1931, Proc. Acad. Nat. Sci. Phila., vol. 83, p. 431. 143 OLSSON: PERUVIAN MIOCENE 143 Corbula tenuis var. lupina, n. var. Platem4 tie sein Shell very similar to typical tenwis but slightly heavier, more narrowly elongate and somewhat coarser sculptured, the con- centric threads becoming distinctly raised on the anterior sub- margins; the escutcheon-like area is larger and narrower; the valves are flexuous with a shallow but distinct sinus through the middle, the posterior side being noticeably more contracted than in typical tenwis; right valve a little larger, overlapping the left along the ventral margin. Length, 18 mm.; height, 9.75 mm.; diameter, 7 mm. Remarks.—Five examples of this Corbula were collected at Tucillal, two specimens having both valves united, the other three being separated valves. They are quite similar to tenws but differ as described above. A species said to be similar to tenuis, was described from the Talara shales by Grzybowski''*, as Corbula lanceolata (renamed Corbula talarana by Hanna and Israelsky™®). If this Corbula is actually from “Stufe ce’, (the Talara or Restin shales) it would be of Eocene age and its near affinities to tenuis would be doubt- ful. I have failed to recognize any of the six species recorded by Grzybowsk1"° from Talara, said to have been collected in the shales forming the lower part of the Talara bluffs. There is a possibility that they are tablazo fossils which have fallen from the overlying rocks. This view is strengthened by the presence of two species of Columbella, a genus of gasteropods having a great development in the recent West Coast fauna. There are no Eocene Corbulas in our collection, resembling lanceolata. Grzybowski’s figure which seems to be a cast, does not show the secondary keels or the escutcheon-like area in the middle of the posterior region. The status of this species cannot be determined without access to the type specimens. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal.. 118Grzybowski, 1899, Neues Jahrb., Beil. Bd. vol. 12, p. 641, pl. 17, fig. 4. 119Hanna and Israelsky, 1925, Proc. Calif. Acad. of Sci., 4th series, vol. 14, p. 64. 120Grzybowski, op. cit., p. 614. 144 BULLETIN 68 144 Corbula (Tenuicorbula) acutirostra Spieker Corbula (Cuneocorbula) acutirostra Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 176, pl, 10, figs. 18, 19. Original description.—Shell of medium size, rostrally truncate, triangular. Anterior margin rounded; ventral margin elliptical; posterior margin sharply angulate, Beaks not prominent, anterior in position, proximate, somewhat flattened above. Anterior surface rounded; mesial surface flat longitudinally and curved vertically. Posterior surface concave, separated from the rest of the shell by a very sharp carina which is bowed, its con- cave side upward. Sculpture of fine and regular graven concentric lines which limit somewhat broader ribs. On the concave surface behind the sharp carina the lines are broader and stronger, recurving toward the hinge, and the elevated ribs are thin and cusp-like. There is a second faint carina near the postero-dorsal margin. The valves are nearly equal, the right being the more inflated, and are equally sculptured. There is neither lunule nor escutcheon. Inner shell unknown. Length, 17.5; height, 10; diameter, 7 mm.—Spieker, 1922. Remarks.—There are no specimens of typical acutirostra in our collections. As shown in Spieker’s figure, the posterior end is strongly contracted, narrowed and quite long. The beaks are nearly central, high, projecting with full, inflated umbones. Spieker mentions no escutcheon in his description, but the escut- cheon-like area limited by the second carina is distinctly shown in the dorsal view of his figure 10. Locality and Geologc Occurrence.—Upper Zorritos, Que- bradas del Grillo and de las Alturas. Corbula acutirostra zorritensis, n. subsp. Plate 14, fig. 3 Shell of medium size to large, inflated, subquadrate ; umbones wide but prominent with a general posterior inclination but with small adjacent and slightly prosogyrate beaks; beaks are near the posterior one-third; the anterior side has the dorsal and ventral margins not quite parallel, the anterior side being broadly rounded ; the posterior side is less than one-half the length of the anterior, strongly flattened so that it appears sharply truncate; the posterior keel is sharp, carinate; a secondary carina outlines an escutcheon-like area in the middle of the posterior area which is broadly elliptical in form; surface is sculptured with fine, con- centric threads, somewhat coarser on the anterior submargins and on the posterior area; deeper, widely spaced lines indicate resting stages; interior unknown. Length, 17.25 mm.; height, 11.75 mm.; diameter, 9.00 mm. 145 OLSSON: PERUVIAN MI0cENE 145 (Holotype). Length, 20.00 mm.; height, 13.50 mm.; diameter, 9.00 mm. Length, 21.00 mm.; height, 14.00 mm.; diameter, 9.50 mm. Remarks.—This Corbula is fairly common in the Upper Zor- ritos. It is probably distinct from Spieker’s acutirostra differing by its shorter, more sharply truncated posterior side and con- sequently less central beaks and umbones. However, the more elongated and older forms have higher, humped umbones and the posterior end becomes somewhat lengthened as seen in Spieker’s figure of acutirostra. However, these are senile char- acters of old, gerontic individuals while Spieker’s specimen is evidently a young and quite typical shell. It is a larger, coarser species than C. tenuis and lwpina. Locality and Geologic Occurrence.—Upper Zorritos of Que. Picos. . Family PANOPEIDZE Genus PANOPEA Menard Panopea cf. coquimbensis d’Orbigny Plate 13, fig. 6 ef. Panopaea coquimbensis d’Orbigny, 1842, Voyage dans 1’Amerique meridionale, Paleontologie, vol. 3, pt. 4, p. 126, pl. 15, figs. 7, 8. ef. Panopaea coquimbensis Philippi, 1887, Die Tert. und Quart. Ver- stein. Chiles, p. 166, pl. 34, fig. 1. ; ef. Panopaea coquimbensis Moreh, Die Tertiarbildungen des nordlichen Chile und ihre Fauna, Neues Jahrb. f. Min. ete., BB. vol, 10, p- 086. Remarks.—The genus Panopea is not known to occur in the recent fauna along the West Coast of South America but no less than eight species have been described from the Chilian Terti- aries. It is doubtful however, that the Chilian species are all correctly placed in this genus. Panopea oblonga Philippi from Guayacan, Chile, closely resembles Panopea americana from the Chesapeake Miocene. There are two specimens of Panopea in our collections from the Peruvian Miocene. A large example from the Tumbez beds of Quebrada Tucillal at Zorritos is a poorly preserved cast with parts of the shell remaining on the umbos. The smaller shell here figured comes from the upper Cardalitos shales in Quebrada Heath near Cerro Bruno. It is somewhat longer than the Tucillal specimen but is probably the same species. The Peruvian forms 146 BULLETIN 68 146 seem related to Panopea coquimbensis d’Orbigny but the original figure of D’Orbigny which is copied by Philippi is based on an internal cast. The Chilian form appears to have higher umbos, the anterior side more strongly contracted and the posterior ex- tremity is shorter. These differences may disappear were the exterior known. Panopea reflexa Conrad from the upper Chesa- peake Miocene of Virginia may be distinguished by its longer anterior side. Morch compared coquimbensis with Panopea gealandica living and fossil in New Zealand. Certain identification of the Peruvian form with coqwimbensis is not possible without comparison of specimens or until the exterior of the Chilian species has been figured. Measurements of the Peruvian specimen is as follows: Tucillal specimen: length, 130.00 mm. ; height, 90.00 mm. ; dia- meter, 61.00 mm. Que. Heath specimen: length, 89.00 mm. ; height, 57.00 m.; diameter, 35.00 mm. Locality and Geologic Occurrence.—Vumbez formation, Que. Tucillal at Zorritos. Cardalitos formation, Upper Que. Heath ~ear Cerro Bruno. Glass GASTROPODA Subclass STREPTONEURA Order CTENOBRANCHIATA Superfamily TOXOGLOSSA Family TEREBRIDAE Genus TEREBRA Bruguiere Subgenus STRIOTEREBRUM Sacco Terebra (Strioterebrum) pavonia, n. sp. Plate 15, figs. 8, 9 Shell of medium size, very slender, with numerous narrow whorls; protoconch unknown; post-nuclear whorls 14 or more, the fasciolar band is large, knobbed by the ribs more than one- third the width of the spire-whorls and limited below by a deep, strong groove; the sculpture consists of strong, curved riblets which cross from suture to suture but are dislocated by the fas- ciolar groove; on the fasciolar band, the ribs are slightly convex forward or face the aperture while on the lower part of the 147 OLSSON: PERUVIAN MiIocENE 147 whorl they are concave forward so that the ribs seem to have shifted backwards or reversed their relative position on cross- ing the fasciolar groove; on the last whorl, the ribs number about 20; spirals are absent or very faint; aperture small. with a short twisted anterior canal provided with 2 folds; base of last whorl contracted. Length, 31.00 mm.; diameter, 6.00 mm. Remarks.—A slender species with a strong, ribbed, fasciolar band and a short anterior canal with 2 columellar folds. Locality and Geologic Occurrence.—Lower Zorritos of Que. La, Cie, Terebra (Strioterebrum) ulloa, n. sp. Plate 15, figs. 1, 2 Shell of medium size, with a moderate taper; nucleus un- known; post-nuclear whorls 12 or more, flattened; sutural band or fasciole about a quarter of the width of the spire-whorl and limited below by a wide, grooved line; most deeply incised on the earlier spire-whorls; the axial sculpture consists of numer- ous, small riblets which curve forward near the fasciolar groove but straighten again across the fasciolar band; these riblets number about 34 on the last whorl on the larger specimens but they are coarser and less numerous on the spire-whorls; spirals are variable in strength and spacing, sometimes as closely spaced, spiral bands, in other cases as more widely spaced spiral threads ; they are usually absent from the fasciolar band which is thus smooth except for the ends of the largest ribs but on the spire- whorls, the spirals usually occur on the fasciolar band as well; anterior canal rather long, twisted, the pillar smooth; siphonal sinus rather strong with a strong, encircling keel. Length, 33 vu mm.; greater diameter, 8.25 mm. Remarks.—This species resembles Terebra gatunensis Toula from Panama but the spiral sculpture consists of finer, more irregular flattened spirals while the longitudinal riblets are finer and more like growth-lines. A small Terebra with two, feebly nodulated cords on each side of the fasciolar band as in Terebra benthalis Dall occurs at La Cruz but the specimens are too frag- mentary to be described and named. Locality and Geologic Occurrence—Lower Zorritos of Que. La Cruz. 148 BULLETIN 68 148 Terebra (Strioterebrum) herviderana Spieker Plater ah eetiesteorat Terebra gausapata var. herviderana Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 35, pl. 1, fig. 1. Original description.—Shell small, delicate, sharply sculptured, the apical angle very small. The fasciole is sharply defined, of medium width. Spiral sculpture on the main part of the whorl of about eight unequal bands sep- arated by narrower interspaces. On the fasciole are vestiges of a spiral sculpture of about three or four fine threads, situated on the upper half of the fasciole, Longitundial sculpture of sharp ribs, 17-18 to the whorl, which are not crossed by the spiral bands. These ribs are cut by the su- ture on one side of the fasciole, where they offset, the rib of one whorl abutting against the interspace on the fasciole of the succeeding whorl. On the other side of the fasciole they are cut by a deeper suture. The body whorl is rounded, and is larger than the preceding whorls. The typi- cal seulpture continues across the base to the columella. The whorls are convex between fascioles. The inner aperture is not known. Height of fragment showing body whorl and two of the spire, 13.5; maximum diam- eter, 5.25 mm.—Spteker, 1922. Remarks.—A small, slender species with strong riblets and irregular spirals. It differs from Terebra gausapata Brown and Pilsbry of which it was considered to be a variety by Spieker, in being smaller, more slender and in having a finer spiral sculp- ture. The fasciolar band usually shows traces of fine spirals. Locality and Geologic Occurrence.—Lower Zorritos forma- tions |Ouer Wa Cruz Terebra (Strioterebrum) zapotalensis, n. sp. - Plate 15, fig. 5 Shell small, slender; nucleus unknown; post-nuclear whorls eight plus, slightly convex with distinct and slightly shouldered sutures; axial riblets strong, curved in the middle, extending from suture to suture and across the base to the contracted zone above the beak or anterior keel; the sutural or fasciolar band is defined simply by a deep, disconnected groove in the spaces be- tween the axial riblets but does not cut across the riblets them- selves; the riblets number about fourteen on the last turn; inter- axial spaces smooth or with very feeble spirals; anterior canal short, encircled by a small keel; columella not visible. Length, 14 mm.; diameter, 3.50 mm. RKemarks.—This is a small species resembling a large Turbon- ila and characterized by its lack of spirals, strong curved riblets and feeble fasciolar band defined simply by a groove in the axial interspaces. Locality and Geologic Occurrence.—Lower Zorritos of Zap- 149 OLSSON: PERUVIAN MIOCENE 149 otal. Terebra (Strioterebrum) nelsoni Hanna and Israelsky Myurella tuberosa Nelson, 1870, Trans. Conn. Acad, Sci., vol. 2, p. 195. (not T. twberosa Hinds, 1843), Terebra tuberosa Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 36, pl. 1, fig. 2. Terebra nelsoni Hanna and Israelsky, 1925, Proc. Calif. Acad. Sci., 4th series, vol. 14, p. 55. Original description.—Shell turreted, slender and acuminate; whorls eight to ten, depressed or slightly concave except the body whorl. Sutures indistinet. Cineture broad, elevated, with obtuse tubercles, not as wide as the spaces between them, .Longitudinal ribs distinct. Whorls marked by from four to six nearly equal transverse ridges, which rise into strong tu- bercles over the ribs. ; Body whorl large, over one-third the length of the shell, depressed above, convex below, rising in the middle into more or less of a shoulder, Shoulder marked by two or three concentric ridges, covered by tubereles much larger than those of the others. Base nearly destitute of tubercles, but with the concentric lines very distinet. Whole surface, on well preserved specimens, marked by fine, minute, longitudinal lines. Aperture elongated-oval; outer lip sharp; columella plicated; canal well reflexed, with the keel only mod- erately elevated. Only three specimens of this species were found all hav- ing the apex slightly broken. Seven whorls give the following measure- ment: length 25.2 millim.; breadth at shoulder 8.4 millim.; breadth at up- per whorl 1.95 millim.—Nelson 1870. Remarks—A fragmentary specimen was found at Tucillal. The species may be recognized by its rather large, apical angle, strong sutural fasciole and even spiral sculpture. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Terebra (Strioterebrum) tafalla, n. sp. Plate 15, fig. 4 Shell small and slender; nucleus unknown; post-nuclear whorls six or more, flattened and lying approximately in the same plane; sutural band of medium width, smooth, except for the ends of strong, fold-like riblets; longitudinal sculpture con- sists of about twenty-one riblets, these are strong on the fasciolar band but on the rest of the shell surface are fine, inconspicuous and merely serve to nodulate the spirals; the spiral sculpture con- sists of nodulated cords and threads spaced as follows: on the spire-whorls there is a large nodulated cord bordering the fascio- lar band, it is bordered on the lower side by a wide groove and then followed by a set of four, small, regular spiral threads; on the body whorl in addition to the spirals just described, the base of the whorl carries a variable number of irregular spirals; an- 150 BULLETIN 68 150 terior canal of medium length, twisted, the pillar with two low folds. Length, 17.5 mm.; diameter, 4.15 mm. Remarks.—This is a small slender species with a peculiar spi- ral sculpture. The longitudinal ribs are quite strong on the fas- ciolar band but are fine and inconspicuous on the rest of the sur- face and serve merely to nodulate the spiral threads. The pillar carries two low folds. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Family TURRIDAE Genus SURCULA H. and A. Adams (sensu lato) Surcula nelsoni, n. sp. ; Plate 16, fig. 10 Shell large or medium-size, solid, smooth; nucleus unknown ; post-nuclear whorls six or more, slightly convex or shouldered by a well-marked but shallow sutural fasciole; suture close but distinct ; body-whorl about half the length of the shell with a stout, straight anterior canal; the surface of the whorls is en- tirely smooth or marked only by the growth-lines ; and with very faint revolving spiral lines; the anal sinus distinct, lying in the sutural fasciole as in typical Surcula; columella covered with a thin callus. Length, 54.00 mm.; diameter, 19.00 mm.; aperture, 20.00 mm. (broken). Length, 43.00 mm. (imperf. specimen); diameter, 16.00 mm.; aperture, 22.00 mm. Remarks.—This is a peculiar form quite unlike any recent or fossil species known to me. The Holotype belongs to the Nel- son collection in the Peabody Museum at Yale University. Locality and Geologic Occurrence-—Tumbez formation, Que. Tucillal. Genus TURRICULA Schumacher Subgenus PLEUROFUSIA de Gregorio Turricula (Pleurofusia) cruziana, n. sp. Plate 15, figs. 6, 10 Shell small or medium size, fusiform; nucleus unknown; post- nuclear whorls 6+, with a slender, fusoid anterior canal; up- per part of whorls contracted, forming a wide and spirally sculp- tured anal faciole; sculpture consists of strong spirals and weak 151 OLSSON: PERUVIAN Mtocenr 151 riblets ; on the spire-whorls there are two, strong, primary spirals which form the shoulder or middle of each whorl; above these central primaries, there are four or five, small secondary threads on the anal fasciole followed by a pimary spiral bordering the suture; below the central primary there are two primary spirals on the spire whorls, the lowest lying almost in the suture while on the body-whorl there are fourteen or more which extend across the base to the tip of the anterior canal; fine, tertiary threads are present in the wide, spiral interspaces ; ribs are weak, number seven or eight on the penultimate whorl; they are present only on the shoulder or middle of the whorl; anal sinus deep, lying in the anal fasciole. Length, 25 mm.; diameter, 8.25 mm.; aperture, 13.5 mm. Remarks.—This species closely resembles Turricula (Pleuro- fusia) pura Olsson’? of the Chira shales but is distinguished by its coarser and more regular primary spirals separated by wide interspaces ornamented with fine tertiaries and differently sculp- tued anal fasciole. In piwra, the anal fasciole is deeply concave and nearly smooth while in cruziana, the fasciole is shallow and sculptured with primary and secondary spirals. The earlier Turricula eolavina Olsson’”? has stronger axial riblets. Locality and Geologic Occurrence.—Zorritos formation, Low- er Zorritos, Que. La Cruz. Family CONIDAE Genus CONUS Linné Subgenus DENDROCONUS Swainson Conus (Dendroconus) bravoi Spieker Plate 16, figs. 1, 3, 4 Conus sp. ind. C. Nelson, 1870, Trans. Conn. Acad,, vol. 2, p, 194. Conus molis var. bravoi Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 41, pl. 1, fig. 6. C. ‘‘molis var.’’ bravoi Woodring, 1928, Carnegie Institute of Wash- ington, No. 385, p. 203. Original description.—Shell large, solid, heavy, The spire very low, al- most flat except at the apex, where the early whorls rise in a nipple-like peak. Whorls twelve to fourteen in number, the last four or five flat to very slightly concave, the remainder flat to convex, The whorls of the spire are depressed, in some specimens at the suture, the edge of the sue- ceeding whorl rising above the suture. Sculpture of moderately arcuate growth-lines on the spire; on the body whorl the growth-lines are prominent 1210lsson, 1931, Bulls. Amer. Pal., vol. 17, p. 214, pl. 21, figs. 9, 13. 122O0lsson, 1930, Bulls. Amer. Pal., vol. 17, p. 34, pl. 3, figs. 2, 9, 10. 152 BULLETIN 68 152 on worn specimens; there is no evidence of spiral sculpture on the spire and upper part of the body whorl; on the lower part of the body whorl are fair- ly coarse spiral threads. p. 647, pl: 19) fies 3: Clavilithes (?) atahuallpai Hanna and Israelsky, 1925, Proce. Calif. Aead. of Sei., 4th series, vol. 14, p. 44, pl. 7, figs. 8, 9. Original description—Schale thurmforming, mit grossem letzten Um- gange. Die Windungen sind stark abgeschniirt. Die friiheren tragen starke Knoten, je 7 auf jedem Umgange, auf dem letzten Umgange sind diese Knoten durch schwache, zwischen seichten Furchen stehende Hocker vertreten. Auf den friiheren Windungen ist auch eine die Knoten querende Spiralstreifung sichtbar (auf vorletztem Umgange 4 Streifen), die auf dem letzten ginzlich ausbleibt. Miindung oval, oben zugespitzt. Innenlippe angeschwollen. Hohe, 40 mm.; Breite, 25 mm.—Grzybowski, 1899. 171 OLSSON: PERUVIAN MIOCENE 171 Remarks.—Grzybowski’s figured specimen which lacked the greater part of the anterior canal was referred to Struthiolaria, the upper part of the shell having some resemblance to this wide- spread and characteristic genus of the southern hemisphere. The species was later redescribed from more perfect specimens by Hanna and Israelsky as Clavilithes (?) athuallpia. The shell has a fairly long, twisted anterior canal encircled by a strong fold arising from the siphonal canal and a small nassoid keel. The early whorls have ribs and spirals, the ribs becoming obsolete on the later turns. The body-whorl is nar- rowly shouldered and sharply contracted about the base. At maturity, a strong, shoulder hump develops near the upper end of the aperture as in Northia northie Gray ( Northia serrata Du- fresne) while the edge of the outer lip becomes sharply serrated. It is clear from these characters that guttifera belongs to North- ia, the only marked difference being the heavier and more per- sistant ribs and spirals on the spire-whorls. Locality and Geologic Occurrence.—Zorritos group, Varie- gated beds, Que. Blanca; Boca Pan. Upper Zorritos, Zorritos ; Punta Picos. Family BUCCINIDZ Genus TRITIARIA Conrad Subgenus TRITIARIA, s. s. Tritiaria peruviana, n. sp. Plate 18, fig. 10 Shell small with a moderately high, stout spire and shorter aperture; nucleus rather large of about three whorls, smooth ex- cept for the last quarter turn which show the feeble beginning of spirals and curved axial riblets, rapidly passing into the post- nuclear sculpture; the post-nuclear whorls are moderately con- vex and number about four; the body-whorl is little more than half the length of the shell; sculpture is reticulate, formed by the intersection of primary spiral threads and somewhat larger, even axial riblets; on the spire-whorls there are four, primary spirals, the posterior one smaller than the others, separated by wide intervals which may be smooth or carry a small secondary ; on the last whorl, the primaries increase to twelve, closely spaced below, spreading apart above; the interspaces may carry a sec- ondary and an occasional tertiary threadlet; there are about 172 BULLETIN 68 172 twenty-one, axial riblets on the body-whorl; these are subregu- larly disposed, extend from the beak or fasciolar spiral to the suture; their intersections with the spirals may give rise on the lower side of the base and near the suture to subspinous eleva- tions or tubercles; aperture subelliptical, with a short anterior canal forming a beak, sculptured with simple, inclined spirals, no riblets and bordered above by a larger but faint keel-like spi- ral; columella provided with a small fold at base; outer lip somewhat thickened, internally lirate and when perfect having a small but distinct stromboid notch near its lower end; siphonal sinus distinct but little recurved. Length, 11 mm.; diameter, 4.75 mm.; aperture, 5.5 mm. Remarks.—The genus Tritiaria has recently been discussed by Woodring in his Bowden Gasteropods. It is based on Buccinum mississippiensis Conrad from the Bryam marl while other spe- cies occur in the Upper Eocene and Lower Oligocene deposits of the Gulf States. About four species have been described from the Peruvian Upper Eocene and Oligocene beds. In per- uviana, the nucleus is somewhat larger than in mississippiensis with the last quarter turn showing the feeble beginnings of spi- rals and axial riblets while in mississippiensis spirals are lacking from, the protoconch. These differences are probably only spe- cific. The finding of Tritiaria in the lower Zorritos Miocene is important as furnishing additional evidence of the paleontologi- cal affinities of these beds to the Oligocene and consequently that they belong low in the Miocene section. Locality and Geologic Occurrence.—Lower Zorritos of Que. Cruz Tritiaria cieza, n .sp. Plate 18, fig. 9 Shell resembling peruviana but smaller and with stronger, axial riblets ; nucleus rather large of about three, smooth whorls, with small, curved riblets and spirals appearing on the last quar- ter turn; post-nuclear whorls about three and a half in number, sculptured with spirals and strong riblets; the spire-whorls have three, strong primary spirals on the first post-nuclear turn, a smaller fourth appearing just below the suture on the second and continuing on the third or penultimate; the body-whorl has eleven spirals, those on the middle of the whorl more widely spaced with a central secondary; on the last whorl, the riblets 7/33 OLSSON: PERUVIAN MIOCENE al Ww numbering eleven, begin at the upper end of the beak, extend to the suture; the riblets being heavier than the spirals, the sculp- ture is less reticulate than in peruviana and the intersections do not become nodose or tuberculate; columella straight with a small fold at the end; aperture subelliptical, the outer lip (im- mature in our specimen) show very faint lire. Length, 9.15 mm.; diameter, 4 mm.; aperture, 4 mm. Remarks.—The single specimen or holotype is probably not quite mature but its nucleus identical with that of peruviana shows that it is closely related to that species. The sculpture is less reticulate than in peruviana, the riblets being larger than the spirals. The internal lirations of the outer lip is very weak indi- cating the immaturity of the specimen. Locality and Geologic Occurrence.—Lower Zorritos of Que. ILa, (Cree Genus PHOS Montfort Subgenus ANTILLOPHOS Woodring Phos (Antillophos) woodringi, n. sp. Plate 18, fig. 11 Shell small, solid, with a fairly high spire and convex whorls; nucleus pointed of three and a half to four small, smooth whorls ; change to the post-nuclear whorls sharp; post-nuclear whorls about five and a half; the first post-nuclear whorl is sculptured with well-defined, narrow riblets crossed by four spiral threads, the first spiral is small and lies close to the upper suture; on the following whorls, the three, lower, primary spirals increase in size, becoming strong and cord-like, and cover the surface of the exposed whorl from the lower suture to the rounded shoulder; above the shoulder is the smaller, first spiral with two still smaller ones between it and the upper suture; interspaces between the spiral cords are deep grooves about as wide as the spirals and sometimes carrying a fine, interstitial thread; riblets are quite strong, persistent and extend on the earlier whorls from suture to suture and on the body-whorl from the anterior canal to the upper suture; the riblets number on the body-whorl about 16, closely crowded back of the aperture; the riblets are nodulated by the spiral cords; anterior canal short, straight, ornamented by spiral threads but without riblets and with a very feeble, siphonal keel; siphonal sinus short, only slightly recurved ; aper- 174 BULLETIN 68 174 ture subelliptical, the columella with small plaits; inner side of outer lip concealed. Length, 14.25 mm.; diameter, 7 mm.; aperture, 6 mm. Remarks.—This is a small species resembling a diminutive Phos gatunensis Toula but with relatively heavier spirals, strong- ly nodulated by the narrow, longitudinal riblets. It is a typical Antillophos but smaller than the heretofore described species. It is named for Dr. W. P. Woodring of the United States Geological Survey and author of the subgenus Antillophos. Locality and Geological Occurrence.—Lower Zorritos of Que- brada Zapotal. Phos (Antillophos) cf. elegans Guppy ef. Phos elegans Guppy, 1866, Quart. Jour. Geol. Soe. London, vol. 22, p- 290, pl. 16, fig. 13. ef, Tritiaria (Antillophos) elegans Woodring, 1928, Carnegie Institu- tion of Washington, No. 385, p. 262, pl. 16, fig. 1. Remarks.—A specimen from Sechura nearly covered with matrix and otherwise imperfect appears closely related to this Bowden species. The shell is somewhat more slender, with a pro- portionately longer spire and coarser sculpture. Its unsatisfac- tory state of preservation renders it impossible to provide a recognizable figure and more certain identification. It probably represents a species distinct but allied to elegans. Locahty and Geologic Occurrence——Montera formation, Bayovar. Phos (antillophos ?) hodsoni, n. sp. Plate 18, figs. 4, 12 Shell of medium size, rather slender; nucleus somewhat wea- thered but seems to consist of 2 1/2 smooth, glassy whorls; post- nuclear whorls about 7; on the first post-nuclear turn, there are strong, axial riblets crossed by two spiral threads; these two spirals gradually lose their primary character by the intercala- tion of secondaries which soon all become of equal strength; the ribs are strong on the earlier whorls, numbering eight to nine on the next to the penultimate turn; after this the ribs become ir- regular and are generally absent from the last whorl part of the penultimate turn and the body-whorl; the spiral sculpture is per- sistant ; on the penultimate whorl there are eight threads between 175 OLsson: PERUVIAN MIocENE 175 the sutures separated by wide, smooth interspaces; on the last whorl and anterior canal, the spirals number about sixteen to the siphonal keel; they are most widely spaced on the middle of the whorl; aperture subelliptical with a strongly thickened lip, usual- ly formed of two ribs; outer lip with about twelve, long, entering lirae ; columella excavated, a fold at the end of the pillar and a short, recurved, siphonal canal bordered by a weak keel. Length, 30 mm.; diameter, 14 mm.; aperture, 14 mm. Length, 31 mm.; diameter 14 mm.; aperture, 14 mm. Remarks.—This species is related to Phos semicostatus Gabb from the San Domingan Miocene but differs by its spiral sculp- ture. The spiral interspaces of semicostatus carry a fine, sec- ondary thread which is more or less nodulated by the growth- lines. This is lacking in the Peruvian shell, the interspaces being smooth with the growth-lines scarcely visible on the body-whorl. The shell is also more slender. Specimens from Zapotal are somewhat larger than those of La Cruz and have stronger, more persistant ribs but are otherwise the same. The ribs are generally absent on the last and part of the penul- timate turns. On some specimens, ribs appear again near the aperture to the extent of four or five ribs. The lip as in semicos- tetus is heavily thickened with one or two ribs. Woodring in his discussion of Antillophos and Engoniophos does not refer to the species of the semicostatus group and evi- dently did not include them in his new genera. They differ from Antillophos by their less cancellate sculpture, the more rib-like, axial folds frequently becoming obsolete on the later turn, a stronger siphonal keel and heavily thickened outer lip. Possibly this group should be considered a section of Antillophos but it requires more detailed study. It includes such species as P. semi- costatus Gabb, costatus Gabb, subsemicostatus Brown and Pils- bry, veatchi Olsson and turbacoensis Anderson. Locality and Geologic Occurrence.—Lower Zorritos of Que. La Cruz, Que. Zapotal; Upper Heath shales or Lower Miocene of Que. Seca-Que. Conchudo, Mancora. Montera formation, Zone A. Bayovar. 176 BULLETIN 68 176 “Phos” phosoides Hanna and Israelsky Plate 20, fig. 4 Siphonalia phosoides Hanna and Israelsky, 1925, Proc. Calif. Acad. Sci., 4th series, vol. 14, p. 43, pl. 7, fig. 10, pl. 8, figs. 5, 7. Original description—Shell fusiform, ventricose with an apical angle of 38, gently shouldered, with a short open canal; sculpture consisting of numerous, nearly equally spaced lirae, those on the base being coarser than the others; where crossed by growth-lines nodules are formed; axial sculp- ture consisting of slightly oblique ribs which become strongest at the shoul- ders where they form nodes (seven on body whorl); sutures slightly raised, undulating; aperture elliptical, produced anteriorly into a_ short open siphonal canal; columella somewhat twisted; altitude 45.4 mm. (spire and canal broken); diameter 21 mm.—Hanna and Israclsky, 1925. Remarks.—Our specimens from Bayovar agree fairly well with the figures and description of Siphonalia phosoides Hanna and Israelsky, described from Corona Peak, Zorritos. It is a solid, rugose form with shouldered whorls, strong ribs and ra- ther coarse spiral sculpturing. On the last turn, the ribs num- ber about seven with the spirals tending to smoothen on the cen- ter of the whorl. The canal is of moderate length with a slightly recurved, siphonal canal bordered by a keel. Our specimens like those of Hanna and Israelsky are not perfect. “Phos” phosides belongs to the group of Phos inornatus Gabb, forms characterized by their large size, shouldered, ribbed whorls, twisted beaks and strong siphonal keel. The spiral sculp- turing is variable, frequently being smooth on the middle of the body-whorl. To this group belongs Anderson’s Phos tuberane- sis from Colombia. I have been unable to identify Corona Peak, Peru of Hanna and Israelsky, the type locality of two Miocene species. The principal hills in the Zorritos district and inland have well-known names and many of them having served as trigonometric station, these names appear on most government and other maps. Locality and Geologic Occurrence.—Zorritos formation, Cor- ona Peak (Hamna and Israelsky). Montera formation, Bayovar. Genus MELONGENA Schumacher Melongena melongena consors Sowerby Plate 19, fig. 4 Pyrula consors Sowerby, 1849, Quart. Jour. Geol. Soe. London, vol. 5, p. 49. ce melongena Gabb, 1873, Trans, Amer. Phil. Soe., vol. 15, p. 205. to 177 Ousson: PERUVIAN MIOCENE 177 Pyrula melongena Guppy, 1874, Geol. Mag., vol. 11, p. 438. Pyrula melongena Guppy, 1876, Quart. Journ. Geol. Soe. London, vol. 32, p. 523. Melongena consors Dall, 1900, Trans. Wagner Free Inst., vol. 3, pt. 1, p. 121. Melongena consors Maury, 1917, Bulls., Amer, Pal., vol. 5, p. 249, pl. 14, fig, 5. Melongena consors Olsson, 1922, Bulls. Amer. Pal., vol. 9, p. 284, pl. 9, fig. 1. Melongena consors Maury, 1925, Bulls. Amer. Pal., vol. 10, p. 360, pl. 35, fig. 12, Melongena consors Weisbord, 1929, Bulls. Amer. Pal., vol. 14, p. 276, pl. 7, fig. 5. Original descriptionTesta obovata, ventricosa, levis, transversim striata; anfractibus quinque, primis tuberculatis, ultimo seriebus duabus ad tribus postice, antice serie solitaria ornatis; apertura oblonga, lata; canali lato, brevi; columell4 antice sub-angulata, planulata.—Sowerby, 1849. Remarks.—Following Dall’s opinion of 1900, it has been cus- tomary to use Sowerby’s name consors for the Miocene form of melongena. Consors is very near melongena and passes through a similar range of individual variation. The recent shell has usually a channelled suture while in consors the sutures are gen- erally close and appressed although a slightly excavated suture is occasionally seen in the fossil as well. Melongena patula Brod. and Sow., the recent West Coast species, differs constantly from melongena by its uniformly darker color, strongly shouldered body-whorl and in lacking the lower row of spines. It is rather surprising to find consors in the Lower Miocene deposits of Peru. Its general rarity and restricted range in the Peruvian section probably indicates that it was but a temporary resident on the West Coast. Large specimens are usually badly weathered. They have the low spire most commonly seen on living melongena but with the closed sutures of consors. The small figured specimen is similar to young, smooth forms of melongena from the Monte Cristo beach of Santo Domingo but have closed sutures and deeper siphonal sinus and stronger fasciolar band. Locality and Geologic Occurrence.—Lower Zorritos of Que. Cruz, Zapotal. Upper Zorritos of Zorritos, Boca Pan. Melongena colombiana Weisbord Plate 19, fig. 1 Melongena colombiana Weisbord, 1929, Bulls. Amer. Pal., vol. 14, p. 275, pl. 7, figs. 2-4. Original description—Shell fairly large, quadrate. Spire shortly conic or conie depressed. Whorls about eight of which the earliest are weathered 178 BULLETIN 68 178 so as to obscure their characters, The body whorl is garnished with three rows of pointed spines each with about 6 spines or 18 in all. The upper row appears at or on the suture; the second row comes at the shoulders of the whorl, and the third about half way down. Between the upper and second series of spines, the whorl is concave with four or five prominent revolving lines; between the second and lowest series there are about nine spiral cords, and about seven below the lower series. Over the whorl are fine arcuate growth striae. The penultimate and the fourth from the last whorl is composed of an itregular blob of calcium carbonate much the same as the Eocene Volutili- thes (Plejona) forms are wont to have. The remaining whorls are sculp- tured with radiating folds which on the third from the last whorl tends to develop into spines near the suture. The folds have a stellate appear- ance when viewed from above and are crossed by revolving striae. The anterior canal is quite broad and somewhat twisted. Umbilicus ob- solete, Above it is a coarse revolving ridge. Inner lip with faint lines — Weisbord, 1929. Remarks.—The occurrence of this recently described Colom- bian species and Melongena melongena consors Sowerby in Peru, two groups now extinct on the West Coast, is additional evi- dence of the complete mingling of the Pacific and Caribbean faunas which occurred during the Miocene. Melongena colom- biana is a striking species, distinguished by its strongly sculp- tured, solid shell, three rows of spines on the body-wohrl, the intervening areas spirally striated and in later life developing a coarse growth of callus at the posterior end of the aperture and which covers the exposed surface of the penultimate and part of the earlier turn, recalling the callused, turbaned spire whorls of Pseudolia mutabilis var. douvillei Olsson of the Peruvian Eocene. The early spire-whorls are free from callus, the sutures stellate by the partly covered first row of spines. The Melongenas like the Senilia group of Arks are typically species inhabiting lagoonal and tidal mud-flats of river-mouths, in more or less brackish waters. The Variegated beds, named from their varicolored shales, lignites, conglomerates and sand- stones were deposited under these conditions. Locality and Geological Occurrence.—Zorritos group, Varie- gated beds of Que. Blanca. Family THAISIDZ Genus THAIS (“Bolten”) Roeding Subgenus STRAMONITA Schumacher Thais (Stramonita) berryi, n. sp. Plate 19, fig. 5 Shell of medium size, the spire rather high, pointed; nucleus 179 OLSSON: PERUVIAN MIOCENE 179 unknown; whorls six plus, between close but distinct sutures ; whorls are moderately convex, those of the spire carinated in the middle by a fine row of tubercles; the body-whorl is about two- thirds or more the length of the shell, broadly biangled by two keels which are widely but not strongly tuberculated; spirals are strong but the axial sculpture is restricted almost entirely to the tubercules; the spirals consist of coarse, primary threads which are rather widely spaced between which there are usually four irregular, finer and closely crowded threads ; aperture semilunar, the columella smooth, somewhat excavated with a small canal at its tip; outer lip broken. Height, 48.00 mm.; diameter, 29.00 mm.; aperture, 32.00 mm. Remarks.—This species is related to Thais biserialis Blain- ville of the West Coast but it differs from any recent specimens I have seen by its more slender form, higher spire and straight, unexcavated sutural slope . The outer laver of the shell is brown- ish in color. This species is named for Professor E. W. Berry of Johns Hopkins University. Locality and Geologic Occurrence.—Tumbez formation, Tucil- lal at Zorritos. Genus SOLENOSTEIRA Dall Subgenus FUSINOSTEIRA, n. subg. Type.—Purpura fusiformis Blainville The following is a description of the Subgenus Fusinosteira: Shell biconic, fusiform, medium weight, the spire and the anterior canal and aperture of about equal length; whorls shouldered, angled, with a wide, shoulder band, the angled shoulder bearing strong, spine-like knobs or tubercules, which are rib-like on the earliest nepionic whorls; in addition, a coarse, spiral sculpturing; aperture widely ovate, melongenoid; anterior canal somewhat twisted, usually with a chink or umbilical canal at its base; a short, recurved siphonal canal; operculum elongate, with an apical nucleus. Remarks.—True Solenosteira Dall with S. (Pyrula) anomala Reeve as its genotype, is a very compact and homogenous group. 180 BULLETIN 68 180 It is characterized by its solid shell, rounded shoulder, obtuse ribs and coarse spirals. Besides anomala Reeve which is a re- cent Panamic species, other typical forms are S. cochlearis and semiglobosa Guppy from Trinidad, S. cochlearis var. magdalen- ensis Weisbord from Venezuela and Colombia, S. dalli Brown and Pilsbry from the Gatun Miocene, S. vaughani Dall from the Chesapeake Miocene of Florida, and its variety medioamericana Olsson from Costa Rica and S. mengeana Dall of the Caloosahat- chei Pliocene. Solenosteira fusiformis Blainville has usually been associated with the Purpuras along with such species at Thais kiosquiformis Duclos while Tryon placed the species with Cymia. Finding that its operculum was non-Purpuroid, elongate with an apical nu- cleus, Dall!*4 in 1910, referred fusiformis to Solenosteira. Fusi- nosteira will be distinguished from true Solenosteira by its more fusoid form, angled shoulder usually provided with sharp, spine- like ribs or tubercles and more irregular spiral sculpturing. Cer- tain species are very similar externally to Cymia but have a simple, unarmed pillar. The classification of these species with true Solenosteira would disassociate an otherwise very natural group. Cuma alternata Nelson from Zorritos, Solenosteira chiri- quiensis Olsson from Water Cay Panama, and Solenosteira fal- conensis Weisbord (S. santaerose Anderson) from Venezuela and Colombia, are referred to this subgenus. Solenosteira fusi- formis Blainville is a recent species ranging from Panama south to the Chincha Islands, Peru. Solenosteira (Fusinosteira) sechurana, n. sp. Plate 21, fig. 2 Shell of medium size, solid, biconic; nucleus unknown; post- nuclear whorls 5, forming a nearly flat, conic spire but with the sutures more or less carinated by the tuberculate shoulder of the spire-whorls; sutures distinct, appressed; the body-whorl is large, sharply shouldered; above the shoulder there is a wide, flattened to slightly concave area, without ribs and sculptured simply by crowded, spiral threads; the shoulder of the last whorl 144Dall, 1910, Proc. U. S. Nat. Mus., vol. 37, no. 1704, p. 167, pl. 22, fig. 3. 181 OLSSON: PERUVIAN MIocENE 181 is angled and bears 8 to 10, undulated but sharp ribs which do not extend above or much below the shoulder angle; the whole surface below the shoulder is sculptured with a primary set of coarse, spiral threads between which there is a set of 3, finer or secondary threads diminishing to 1 on the canal; the spirals above the shoulder are finer and alternating; growth-lines sinu- ous, convex forward across the lower half of the whorl, slight- ly concave forward above the shoulder; columella wide, thick- ened, somewhat excavated and plain; aperture subelliptical, interior of outer lip concealed ; tip of canal broken. Length, 36 mm. ; diameter, 24 mm. ; aperture, 21.5 mm. Length, 40 mm.; diameter, 28 mm. Remarks.— Externally, this species bears considerable resem- blance to Cymia but the pillar is simple and unarmed. ‘The tip of the anterior canal is broken so the presence or absence of an um- bilical cleft is unknown. The knobbed ribs are confined to the shoulder angle and vary slightly in size on different individuals. Locality and Geologic Occurrence.—Montera formation, Zone A, Bayovar. Solenosteira (Fusinosteira) alternata Nelson Cuma alternata Nelson 1870, Trans. Conn, Acad., vol. 2, p. 198, pl. 7, figs. 3, 4. Solenosteira alternata Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 45, pl. 1, figs. 10, 11. Original description.—Shell slender, fusiform; spite elevated, turreted and pointed; whorls six or seven, convex, separated by well-marked su- tures and ornamented by a series of rather prominent ridges, about eight to each whorl. Ridges rise in the middle of each whorl into obtuse tuber- cles. The body whorl is large, somewhat ventricose, about two-thirds the length of the shell, very convex, broadest about one-fourth from the top of the whorl or near the middle of the shell. Ridges on this whorl are very distinet, but gradually disappear as they approach the suture, and are entirely wanting over the lower half of the whorl. Surface marked by raised revolving lines, arranged in two series; between every two of the larger ones there are from one to five smaller, nearly equal ones; about six of the larger in the space of 5 millim. Striations much larger on the lower part of the body whorl. Aperture oblong-oval, half as long as the shell. Outer lip with a row of small, equidistant teeth, six in the space of 5 millim., but which do not extend into the interior of the shell. Col- umellar lip smooth and overspread with callus. Canal wide, open, and reflexed, Umbilicus small, redueed to a mere chink in most specimens, bordered by a large well defined keel. Length 52 millim; breadth 33.4 millim.—Nelson, 1870. 182 BULLETIN 68 182 Remarks.—The Holotype which belongs to the Nelson col- lection at Yale has been figured by Nelson and later by Spieker. The species is not in our collection from Tucillal but the color and preservation of the examples in the Yale collection show that it is a member of the Tumbez fauna. Solenosteira alternata differs from sechurana by its more angled shoulder and stronger but fewer ribs. An unidentified recent species quite similar to alternata, was collected on the beaches of Santa Elena and San Pedro Ecuador. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Genus CY'MIA Morch Cymia pilsbryi, n. sp. ; Plate 19, fig. 2 Shell medium size to large, biconic; nucleus unknown; early nepionic whorls with three beaded spirals, the first lying next to the upper suture, the other two more widely spaced, the third or lower spiral bordering the lower suture; on the following whorls, additional spirals are introduced, the primary ones losing their beading and the sculpture becoming irregular; at the same time ribs are introduced along the lower suture and as the coil- ing of the whorls descends, the ribs increase in size, forming a shouldered or peripheral zone to each whorl; when mature, the whorls number five plus, exclusive of nucleus; the last whorl has a strongly angled, carinate shoulder; the area above the shoulder or peripheral angle is wide, flat and sculptured with about eight, wide, flat or banded spirals, separated by fine, incised lines ; below the periphery, the whorl is contracted in the middle or columellar region and similarly sculptured with banded spirals ; the periphery or shoulder is strongly angled and bears about ten, sharp, flattened (in plane of shoulder), tooth-like nodes or tubercles limited entirely to the shoulder angle; on the penulti- mate and earlier turns, these tubercles are visible above the suture as the coiling of the whorls lies below the peripheral angle; anterior canal of usual length, its end carrying a strong umbilical rib encircling a narrow, umbilical cleft in the middle; interior of young shells have a strong, revolving cord on the middle of the pillar; outer lip unknown. 183 OLSSON: PERUVIAN MIOCENE 183 Length, 47 mm.; diameter, 38.5 mm.; aperture, 35 mm. Remarks.—This well-marked species is easily distinguished by its numerous, tooth-like shoulder tubercles. Cymia buchiva- coana'*® recently described by Mrs. Hodson from the Vene- zulean Miocene, has similar shoulder tubercles but is larger and has strong, cord-like basal spirals. The coiling of the later turns lies beneath the shoulder angle so that the penultimate and one or more of the earlier turns, are coronated by the tubercles as seen in certain species of Fulgur. Very young shells have a sculpture of beaded primary spirals. On the mature whorls, the spirals are wide bands, feebly separated from each other by fine lines. As Pilsbry**® has pointed out, in recent C. tectum Wood, the spirals are coarse and divided by deeply engraved grooves. This species is named for Dr. H. A. Pilsbry of the Academy of Natural Science of Philadelphia. Locality and Geologic Occurrence.—Lower Zorritos of Que. La Cruz, Que. Higueron and Zapotal. Genus ACANTHIZA Fischer Subgenus CHORUS Gray Acanthiza (Chorus) solida Nelson Clavella solida Nelson, 1870, Trans. Conn. Sci., vol. 2, p. 199. Pyrula roseata Grzybowski, 1899, Neues Jahrb. f. Min., ete., Beil. Bd. 12, p. 648, pl. 19, fig. 6, Triumphis solida Spieker, 1922, Johns Hopkins University, Studies in Geology, No, 3, p. 49, pl. 2, fig. 3. Original description.—Shell oval, ventricose, and heavy; spire moder- ately elevated and tapering. Whorls five to seven, more or less depressed above. Sutures distiet. Body whorl large, more than two-thirds the length of the shell, regularly convex, depressed above the shoulder, which is large and strong, and forms a very distinct ridge, extending more than half around the shell. The upper whorls are marked by a series of longitudinal ridges, eight or ten to a whorl, and crossed by strong, equidistant, revolving lines. The two lower whorls are destitute of the ridges, but ornamented by revolving lines, which become more or less indistinct on the body whorl in mature specimens. The base of the body whorl is marked by much stronger lines. Variable in size. Aperture oblong-oval; outer lip thin. Canal long and 145H. K. Hodson, 1931, Bulls. Amer. Pal., vol. 16, p. 38, pl. 18, fig. 4, pl. 22, fig. 2. 146Pilsbry, 1922, Proc. Acad. Nat. Sci. Phila., vol. 73, p. 355, 184. BULLETIN 68 184 slightly reflexed. Umbilical chink bordered by a broad keel, Measure- ments as follows: length 43.2 millim; breadth (at shoulder) 30.6 millim.; breadth (below shoulder) 28 millim.—WNelson, 1922. Remarks.—-Nelson compared solida with Cantharus distortus (Gray) Woods, a recent Peruvian - Panamic species and type of Gray’s genus Triumphis. The pronounced thickening of the posterior end of the lip and infolding of the anterior end of the canal, forming a narrow umbilical chink, are principally char- acters of senility and it is doubtful that they possess a high sys- tematic value. Our specimens are too badly broken and worn to be figured. Grzybowski’s figure shows the apertural view of a fairly com- plete specimen while Spieker has figured the dorsal side of the lectotype from the Nelson collection. Spieker accepting Nelson’s view as to the near relationship of solida to Cantharus distortus referred the fossil directly to Triumphis. However the two species are not closely related, solida belonging with Acanthiza (Acanthina) and Chorus to the Thaiside. Clues as to the systematic position of solida are best furnished by the following new Oligocene species. Even the young shells have strongly shouldered whorls, a low conic to flattened spire, a deep, Pseudoliva-like groove arising from an apertural tooth, a strong, twisted siphonal canal forming a large, fasciolar fold usually enclosing a small umbilicus at its end, Gastridium cepa Sowerby described from Navidad, Chile, is probably related but the whorls are rounded and not shoul- dered. Gastridium Sowerby, is usually incorrectly consid- ered a synonym of Pseudoliva. Locality and Geologic Occurrence.—Cardalitos formation, Caleto Grau, Upper Que. Heath, Que. Charan. Acanthiza, (Chorus) voluta, n. sp. Plate 19, figs. 3, 6, 7 Shell of medium size, solid, a low conic spire and strongly shouldered whorls; nucleus unknown; whorls five or more, sep- arated by deep, channelled sutures; early nepionic whorls have seven or eight, strong ribs and spirals; the ribs disappear rapid- ly and are absent from the last two and half turns; the spire is low, conic becoming sub-concave in profile by the flattened, shoulder area; narrowed and contracted below the base to form a short, anterior canal; large shells usually have the body-whorl 185 OLSSON: PERUVIAN MI0cENE 185 contracted in the middle or along a zone just below the shoul- der; a strong, Pseudoliva-Acanthiza groove encircling the shell, emerging from the middle of the inner lip and probably ending in a labial tooth; below this groove there are fine, spiral bands defined by obscure spirals; above the Acanthiza-groove, the sur- face is smooth or marked with faint growth-lines ; siphonal sinus deep, forming a strong fold which encircles a narrow umbilical pit in the end of the anterior canal, variable, scarcely visible in young shell but becoming larger with age: Height, 32 mm.; (imperfect); greater diameter, 29 mm. Length, 23 mm.; greater diameter, 19 mm. Height, 26 mm.; greater diameter, 22 mm. Remarks.—Although the locality of these specimens is not certainly known, they are described in this place because of their bearing on the generic affinities of solida Nelson. They were probably collected at the base of the Heath shales where they overlie the Punta Bravo grits in upper Quebrada Zapotal and occur with a large form of Turritella conquistadorana Hanna and Israelsky. They therefore belong to the Caleto Mero fauna of basal Upper Oligocene age. From solida, they differ by the smaller size, smoother whorls, more deeply channelled sutures and generally higher spire. Philippi’s!*7 Monoceras laevis from Chile is somewhat like this species but differs by its more con- vex and non-shouldered whorls. It is obvious that voluta and solida cannot be referred to Gray’s genus Triumphis, its affinities with Acanthiza being un- questionable. Locality and Geologic Occurrence——Heath formation, basal Heath shales of Upper Que. Zapotal ? Acanthiza (Chorus) sula cruziana, n. subsp. Plate 20, fig. 7 ef. Acanthina (Chorus) sula Olsson, 1931, Bulls. Amer. Pal., vol. 17, p. 203, pl. 18, figs. 1, 2. Shell fasciolaroid, thin, with a large body-whorl and shoul- dered whorls; nucleus unknown; post-nuclear whorl four plus, separated by close but distinct sutures and forming a spire of medium height; whorls angled, shouldered, the area above the shoulder slightly depressed but with a low cord or keel border- ing the suture; sculpture of faint, subobsolete spiral bands, 147Philippi, 1889, Die Versteinerungen Chiles, p. 65, pl. 5, fig. 8. 186 BULLETIN 68 186 strongest on the base while the middle of the whorl is nearly smooth; anterior canal broken. Height, 20 mm. (imperfect) ; diameter, 26 mm. Remarks.—Acanthiza sula was described from the basal Heath shales of Caleto Mero and a badly crushed specimen was also collected at Posorja in beds of the same age. The single specimen from the Lower Zorritos of Quebrada La Cruz is probably distinct, differing from sula by its narrower shoulder. As the types of sula are not well preserved, detailed comparison of sculpture is not possible. A form related to A. sula occurs in the Lower Miocene beds at Barranca near Punta Arenas, Costa Rica. It differs from the La Cruz shell by its coarser sculpture. How great value should be given to these differences cannot be determined from the material at present available. Locality and Geologic Occurrence.—Lower Zorritos of Que. aa @ruz Superfamily TAENIGLOSSA Family BURSIDA Genus BURSA (“Bolten”) Roeding Subgenus CROSSATA Jousseaume Bursa (Crossata) ventricosa Broderip var. _ Plate 21, fig. 1 ef.Ranella ventricosa Broderip, 1832, Proce. Zool. Soc., p, 178. ef. Ranella ventricosa Sowerby, 1836, Conch. Ill., pl. 92, fig. 16. ef. Ranella ventricosa Reeve, 1844, Conch, Icon., pl. 2, fig. 6. Shell rather large, moderately heavy with an elevated spire and-large body-whorl; nucleus and sculpture of early spire- whorls not known; whorls 6+, shouldered, armed with strong, pointed tubercles, there being usually 6 on each spire-whorl; on the last whorl there is a zone of 6 large tubercles on the upper side of the whorl and 2 smaller ones on the middle zone in front of the first varix; in addition, the body-whorl is sculptured with strong, ribbon-like bands, widely spaced and with smaller, weak- er ones in between; varices somewhat heavier than in typical ventricosa; outer lip thickened, irregularly crenate and a wash of callus over the inner lip or body-whorl; anterior canal, short, impressed above in the columellar region and with a short, re- curved anterior sinus; posterior sinus deep, lying at the junction of the outer lip and body-whorl or along the suture. 187 OLSSON: PERUVIAN MIOGENE 187 Height, 56 mm.; diameter, 43 mm.; aperture, 34 mm. Height 57 mm.; diameter, 39.5 mm.; aperture, 32 mm. Remarks.—The subgenus Crossata was proposed by Jousse- aume in 1881 with Ranella ventricosa Broderip as type. In this singular species, the varices are feebly developed and not con- tinuous but follow a short distance back of each other on ascend- ing and crossing the spire-whorls. The whorls are shouldered, bearing strong tubercles. On the last whorl the tubercles show an unusual arrangement, those on the back of the whorl being lower on the left half than on the right or aperture side. The posterior sinus is a deep, beveled notch at the junction of the lip with the body-whorl and the trace of this sinus is seen on the earlier varices. The range of Bursa ventricosa as a recent species is given by Dall™*® as the west coast of Nicaragua to Callao Peru. It is fairly common at Bayovar, Bay of Sechura and a few specimens were also collected on the shores of Lobos de Tierra. Hupe™® and Reeve unite Ranella tenwis Potiez and Michaud with ventri- cosa which would extend its range to Chile. Bursa (Crossata) californica Hinds'*® from Lower California, is very similar to ventricosa and may prove to be but a large variety or subspecies of the Peruvian species. The fossils from Tucillal are heavier and more strongly sculptured than typical ventricosa but otherwise are very similar to the recent shell. They show the same peculiar arrangement of the tubercles on the back of the body-whorl. Locality and Geologic Occurrence-——Tumbez formation, Que. Tucillal at Zorritos. Subgenus MARSUPINA Dall Bursa (Marsupina) freya, n. sp. Plate 21, figs. 3, 4, 6 Shell small, solid, biconic; nucleus naticoid of 3 1/2 smooth whorls, the change to the post-nuclear, abrupt; post-nuclear 148Dall, 1910, Proc. U. S. Nat. Mus., vol. 37, p. 226. 149Hupe 1854, Fauna Chilena Moluscos, In Gay, Historica fisica y politica de Chile. Zool., vol. 8, p. 184. 150Reeve, Icon. Conch., Ranella. sp. 9. 188 BULLETIN 68 188 whorls about 3 1/2; the spire is high, conic; the body-whorl is large, expanded and wide above, contracted below to form a short but distinct anterior canal; varices strong, crenate but not spiniferous, continuous, there being two to each whorl spaced about 180 degrees apart; the intervarical spaces each have two, small knob-like humps and the whole surface is sculptured with fine to medium, coarse, alternating, beaded spirals; sutures sharp and distinct; aperture elliptical, strongly callused, contracted above into.a long, narrow, posterior sinus extending upward and beyond the suture; anterior canal of medium length, slightly bent backwards; outer lip thickened, internally crenulated; a wash of callus on the body-whorl and bearing several, elon- gated denticles. Length, 23 mm.; diameter, 17 mm.; aperture, 17 mm. Length 23 mm.; diameter, 18 mm.; aperture, 17 mm. Remarks.—Our collection contains ten specimens, six being quite perfect. They differ from the group of Bursa crassa Dillwyn which includes proavus and bowdenensis of Pilsbry by their smaller size, shorter shell and proportionately larger body- whorl. Bursa chira and its variety yasila Olsson from _ the Peruvian Upper Eocene and Oligocene deposits is typically a shorter form with wider, more expanded varices. The aperture and callus of the parietal wall is often colored brownish, strong- ly contrasting with the lighter tint of the shell. The stratigraphic position of this Bursa is somewhat uncer- tain. They were collected from the synclinal area of Quebrada Seca, occupied by the Heath shales and capped by thin remnants of more sandy beds. It is thus possible that they belong to some sandy horizon in the upper Heath shales or these sandy beds may represent the basal Miocene. If this later view is correct, they indicate a small embayment of the Zorritos Miocene south of Punta Brava. Locality and Geologic Occurrence.—Divide occupied princi- pally by the Heath shales between Quebrada Conchudo Bravo and Quebrada Seca, Mancora. 189 OLSSON: PERUVIAN MIOCENE 189 Family CYMATIIDAE Genus DISTORSIO (“Bolten”) Roeding Subgenus DISTORSIO, s. s. Distorsio decussatus ringens Philippi Tritonum ringens Philippi, 1887, Die Tert, und Quart. Verstein, Chiles, p. 06, pl. 4, fig. 9. Original description—Testa mediocris, oblongo-fusiformis, distorta; an- fractus rotundati, gibbosi, cingulis elevatis angustis, nodulos acutos gerenti- bus ornati, posteriores cancellati; aperteur ringens. Longit, usque ad 66, erass. 36 mm.—Philippi, 1887. Remarks.—Woodring’s discussion of the Bowden Distorsios and the distribution of this genus in the Miocene deposits of the Caribbean region is of considerable interest and importance. Two groups of Distorsio, both of which occur at Bowden are distin- guished, the smoothly humped, evenly reticulated gatunensis Toula as a variety of the West Indian clathratus and the angular humped, unevenly reticulated simillimus Sowerby as a variety of the Pacific decussatus Valenciennes (constrictus of Broderip). According to Dall, both clathratus and decussatus (as reticulata) types are said to be recent in the West Indies, but the common West Indian species is clathratus and the Pacific species is decus- satus. A distinguishing feature of decussatus is the double spiral band on the shoulder which is simple in clathratus. The sub- sutural band in decussatus is also double but much finer. Typical decussatus from the Pacific is usually easily distin- guished from szmillimus Sowerby by its coarse, spiral sculpture, there being usually only a single spiral cord between the shoulder and the sutural cord while this area in San Domingo specimens of simillimus carries many fine to coarse spirals. A single specimen of a Distorsio was collected from the Low- er Zorritos beds at Zapotal. It is unfortunately covered with a film or coating of gypsum which partly conceals the details of the sculpture. Its humped whorls and double shoulder band shows that it belongs to the decussatus group but is smaller than the average decussatus, the whorls are less angulated and the ante- rior canal is longer. The spiral sculpture is quite coarse with a single cord lying in the area between the shoulder and the suture as in living decussatus. Philippi described two species of Distorsio from the Chilian 190 BULLETIN 68 198 Tertiaries. D. thersites Philippi (op. cit., p. 56, pl. 4, fig. 8) 1s a large, rugose shell with a length of 73 millimeters. It bears much resemblance to clathratus in form and sculpture of its ear- lier whorls but the reticulate pattern disappears on the body- whorl, leaving the spiral bands plain or only distantly noded. D. ringens Philippi from Navidad and Matanzas seems to be a vari- ety of decussatus, having strongly angulated whorls and a double shoulder band. The anterior canal is quite long. The Zapotal shell is tentatively referred to Philippi’s ringens as a variety of decussatus but has a shorter spire and broader, less angled body-whorl. The most southerly known occurrence of recent decussatus is Lobitos, Peru, (there are beach specimens in our collection) so that the extension of this group as recog- nized in ringens into the Chilian Tertiaries is important from a faunal and distributional standpoint. Locality and Geologic Occurrence.—Lower Zorritos of Que. Zapotal. Family Pyrenidae (“Columbellidae”) Genus STROMBINA Morch Subgenus STROMBINA s. s. Strombina (Strombina) tumbezia, n. sp. Plate 18, fig. 7 Shell small or medium-sized; nucleus long, slender, composed of about three, smooth whorls; post-nuclear whorls about five, nearly flat, with a ridge or cord bordering the suture and orna- mented with strong ribs; body-whorl columbelloid, smooth dor- sally but not dorso-ventrally flattened as in many species of Strombina; ribs on the penultimate whorl numbers about thirteen, they are slightly curved in the middle and separated by wide, smooth interspaces; the ribs occur on the ventral face but are absent from the dorsal side of the body-whorl on mature speci- mens ; there are eight spiral cords on the anterior canal but spirals are lacking from the rest of the shell; aperture narrow, elliptical, the outer lip strongly thickened and internally denticulate ; colum- ella straight with a callus shelf, feebly lirated by the underlying spirals. Length, 10 mm.; diameter, 4.5 mm.; aperture, 4.15 mm. Remarks.—In its sculpture, this species resembles S. sincola 191 OLSSON: PERUVIAN MI0cENE 191 Olsson from the Costa Rican Miocene, but is larger, with a less thickened outer lip not indented on the dorsal side. The sculp- ture consists of strong, slightly curved, smooth riblets ending at a strong sutural cord. They are absent on the dorsal side of the body-whorl. Locality and Geologic Occurrence.—Lower Zorritos, Que. La Cruz. Strombina (Strombina) lanceolata zorritosensis, n. subsp. Plate 18, figs. 8, 13 Strombina lanceolata Nelson, 1870, Trans. Conn. Aead., vol. 2, p. 198. (not Columbella lanceolata Sowerby, 1832). Shell like S. lanceolata Sowerby, but smaller at maturity, more stubby in form and with a heavier, more solid outer lip. Remarks.—This Strombina is a common gasteropod in the Tucillal deposits. At maturity, the shells are constantly smaller than full-grown lanceolata, specimens of lanceolata of the size as the Tucillal fossils still have a thin or juvenile outer lip. The form is also more stubby, the shell a little more solid and the outer lip more heavily thickened. Since these characteristics seem to be constant amongst the fossils, it is deemed advisable to recognize these distinctions by a varietal name. The fine, honey- comb-like markings which distinguish lanceolata may be seen on the better preserved specimens of gorritosensis. Locahty and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. Genus CERITHIUM Bruguiere Cerithium infranodatum Spieker Cerithium infranodatum Spieker, 1922, Johns Hopkins University, Studies in Geolody, No. 3, p. 56, pl, 2, fig. 9. Original description.Shell large, tapering moderately, nodose, the su- tures distinet, but slightly impressed. Whorls 10-12 in number; the early whorls decorated with numerous longitudinal ridges which are slightly arcuate, each with four lateral nodes caused by spiral sulei which cross both ribs and interspaces; with the growth of the shell the longitudinal ribs become less numerous and more widely- spaced; on about the seventh whorl they are larger, broader, and not so deeply cut by the spiral grooves; and on the last two to four whorls they center into strong, round, pustulk: wr tubercles situated below the median line of the whorl, and in some speci- mens near the base of the whorl. On the specimens examined, which are badly worn, it is difficult to tell whether or not the spiral sculpture con- tinues, but lines of growth are evident. Aperture unknown. Height of fragment bearing 4.5 “whorls, 58.5; maximum diameter, 27 mm.—Spieker, 1922. 192 BULLETIN 68 192 Remarks.—This is a large Melantria-like species, the early nepionic whorls have a cancellate sculpture while the later turns are nodulated by strong, tubercular riblets. The mature form has a broad, expanded lip forming resting marks at intervals. Locality and Geologic Occurrence.—Zorritos group, Variegat- ed beds at Boca Pan. Que. Heath. Cerithium grillanum Spieker Cerithium grillanum Spieker. 1922. Johns Hopkins University, Studies in Geology, No. 3, p. 57, pl. 2, fig. 10. Original description.—Shell small to medium-sized, highly ornate. Whorls probably eight to ten in total number, Sculpture of transverse nodes erossed by spiral cords; on the earlier whorls the nodes are long and un- differentiated, appearing in worn specimens as cogs; on the later whorls of the spire they are differentiated into two series through the swelling laterally of their upper and lower parts, and not through mesial sulcation; the upper of the two series gradually becomes the more prominent until on the body whorl the lower nodules are almost obsolete, and three addi- tional rows of nodules, really nodulate spiral straps appear on the basal surface. There is some variation in the differentiation of the nodules; on some specimens the upper series gains the ascendancy well up on the shell, whereas in others the rows are subequal until the penultimate whorl, In specimens which show early differentiation of the two series of nodes the lower series contains more nodes than the upper. A series of fine spiral cords, which are weaker on the nodes, covers the whorls. On the base of the body-whorl there are two or three cords between the noded straps; thence upward they are similarly distributed over the nodose whorls. Aperture unknown. Height of specimen bearing 4% whorls, 32; diameter, 16 mm. —Spieker, 1922. Remarks.—This Cerite is not uncommon but it is usually brok- en or worn. It is distinguished by its strong, axial riblets, the lower ends of which are nodulated by a strong spiral cord. The base of the shell is sculptured only with beaded spirals. Locality and Geologic Occurrence.—Zorritos group, Variegat- ed beds of Quebradas del Grillo, del Toro, de los Angeles and Fleatha(Spieker)); @Que, Blanca Bocayranw Punta ieicos: Genus POTAMIDES Brongniart Potamides bocapanensis, n. sp. Plate 20, fig. 8 Shell short-turreted, solid, five whorls remaining on type speci- men, the summit truncate and closed by a plug; tip of spire and very early spire-whorls unknown, the others are flat to slight- ly depressed in the middle, smooth; the body-whorl is rather large, convex, the base rounded, passing into the medium-length anterior canal or beak; growth-lines sinuous, a broad shallow sinus in the middle of each whorl; aperture with the outer lip 193 OLSSON: PERUVIAN MIOCENE 192 broken, its junction with the body-whorl thickened as well as the columellar region. Height, 28 mm.; diameter, 16.5 mm. Remarks.—This species will be recognized by its short, tur- reted form and nearly smooth, unornamented whorls. Other specimens from Boca Pan may belong to a more slender species with a groove encircling each whorl near the middle. This last form somewhat resembles Potamides caobasensis Pilsbry'®! from Haiti but is probably distinct. Locality and Geologic Occurrence.—Zorritos group, Variegat- ed beds at Boca Pan. Potamides infraliratus Spieker Plater2on eseipste Potamides ormei, var. infraliratus Spieker, 1922. Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 58, pl. 2, fig. 11. Original description.Shell large and solid, the whorls closely coiled, the apical angle moderate. Early whorls unknown; the complete shell might have ten or twelve whorls. Whorls usually flat, sometimes slightly convex, the sutures ordinarily indistinct. Cancellate sculpture of quadrate beads formed by the intersection of longitudinal and spiral grooves which set off strap-like ribs, the longitudinal grooves are arcuate on each whorl, and are about 30 in number to the whorl; the spiral furrows set off three rows of beads of which the anterior two are subequal in width and the posterior- most is much broader, Beneath the beads of the body whorl are seven or eight strap-like spiral ribs which form the basal sculpture. The body whorl flares at the aperture, the sculpture opening out in fan-shape, and the su- tural margin ascending to cover part of the preceding whorl. The aperture is large, pointed, oval in shape, with the outer lip strong and thickened and the callus heavy. The posterior notch is distinct, the anterior canal is truneate, sharp. Height of fragment bearing the lower four whorls, 37 mm.; maximum diameter at base, 24 mm.; at 4th whorl, 10 mm. A longer fragment, bearing 5 whorls, but lacking the outer lip of the aperture, is 41 mm. in height, and probably had a maximum diameter of 27 mm. —Swpieker, 1922. Remarks.—The Peruvian fossils appear distinct from the San- to Domingan orymei Maury in having the upper beaded cord con- stantly larger and heavier as pointed out by Spieker. Locality and Geologic Occurrence.—Variegated beds, Boca Pan. Punta Picos. Family TURRITELLIDAE Genus TURRITELLA Lamarck Turritella prenuncia Spieker Plate 23, figs. 8, 9 Turritella prenuncia Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 81, pl. 4, figs. 1-3. 151Pilsbry, 1910, Proc. Acad. Nat. Sci. Phila., vol. 62, p. 488, fig. 2; also Woodring and Brown, 1924, Geology of the Republic of Haiti, p. 183, DISD eSee LO men 194 BULLETIN 68 194 Original description.—Shell small, delicate, the apical angle moderate, whorls fairly tight-coiled, sutures distinct. There appear to be two types of early development, each of which attains the same end result in the fully mature whorls, but which are sufficiently different in the neanic whorls to deserve notice. The two types are here described separately, being noted for convenience in reference, as (a) and (b), (a). Protoconch bulbous, consisting of one and a half turns, Neanic whorls carinate, strongly sculptured by cordate threads, of which there are three on the first whorl, the anterior-most the strongest forming the carina. On the second whorl a fourth faint thread appears above the posterior-most of the three mentioned, and on the third whorl an intermediate thread appears behind the carinal thread, as well as a subsidiary thread before the carina. On the fourth whorl the subsidiary threads have grown equal in strength to the others. This sculpture of six equal threads continues over the rest of the shell, with the introduction of faintly visible inter- mediate threads between the first and second, third and fourth, and fourth and fifth threads, and the addition of a faint posterior thread near the suture. The fifth whorl is rounded in outline, the carina having lost promi- nence, and succeeding whorls are more rounded, with the point of maximum diameter at the location of the obsolete carina. (b). Neanic whorls strongly carinate, the carina at the anterior third, accentuated by a coarse thread. The first three whorls below the proto- conch bear two prominent cordate threads, of which the anterior one, on the carina, is stronger; on the fourth whorl a faint thread appears on the basal surface before the carina; this is strengthened on the fifth whorl, where another light thread appears above the posterior of the two original ones. On the sixth whorl there occurs in addition a faint intermediary thread, between the original two, which have lost strength, comparatively ; on the seventh whorl the threads mentioned approach equality, in strength, and a faint posterior thread appears. The characteristic adult sculpture of the species is attained in the eighth whorl the interposition of a subsid- iary thread between the fourth and fifth of those named for the preceding whorl. The seventh and eighth whorls are more evenly sculptured and contoured, the carina being obsolescent, and all the threads save the 5th and 7th attaining equality in strength. Length of eighth whorl of form (a), 20 mm.; of form (b), 11 mm.— Spieker, 1922. Remarks.—Type (a), illustrated by Spieker’s figure 1, in which the whorls are sculptured with fairly even spirals is the most common fornr at Zapotal and is considered as typical pre- nuncia. At maturity, the whorls are slightly convex to flattened, broadest about the base and overhanging the lower suture. There are Six or seven, primary spiral threads on the spire-whorls sep- arated by wider intervals which may be smooth or each carrying a single secondary thread. The base of the last whorl is flattened and defined by the sutural cord and scu!ptured simply by small, weak spirals. The growth-lines, like those of infracarinata be- long to Guillaume’s Class 4. . 195 OLSSON: PERUVIAN MIOCENE 195 Our specimens are much larger than those of Spieker. A specimen of five whorls lacking the spire measures: length, 38 millimeters, diameter, 12.5 millimeters or an estimated total length of 50 millimeters when perfect. It is a common species in the Lower Zorritos of Zapotal and Que. La Cruz. Turritella prenuncia cruziana, n. subsp. Plate 23, figs. 6, 7 Shell of medium size, slender; in our specimen, the proto- conch is lost with the tip of the nepionic whorl sealed by a small, convex septum; the smallest nepionic whorls seen are strongly convex, sculptured usually with two strong, primary spirals with smaller threads in the sutural band above and between them; as the two primary spirals remain much stronger than the others and separated by wider intervals, the face of the whorl becomes biangular; the spiral interspaces may remain smooth or contain only very fine, subobsolete spiral lines or an occasional secondary thread may appear in one or more of the interspaces; the base of the whorl is flattened to excavated and sculptured with very small spirals. Length, 44 mm.; diameter, 11 mm. Remarks.—Extreme specimens appear quite distinct from typical prenuncia but the flattened, weakly sculptured base and the smoothish spiral interspaces show that the forms are close- ly related. It is possibly that this subspecies, corresponds to Spieker’s type (b) but we have no specimens of this form from Zapotal. The nepionic sculpture is not constant, in some speci- mens the uppermost of the two primary spirals may become en- larged while in others it is the lower. Locality and Geologic Occurrence——Lower Zorritos of Que. icanGruz Turritella fica, n. sp. Plate 22, figs. 3, 9 Shell of medium size, with numerous, convex and finely sculp- tured whorls; nucleus and early nepionic whorls unknown; the later whorls are convex but wider about the lower half so that the slope towards the upper suture is gentle and nearly flat while the lower half is convex and ascends sharply into the anterior suture; sutures distinct, overhung by the preceding turn; the last whorl is evenly convex, the base not sharply limited; the 196 BULLETIN 68 196 sculpture consists of fine, irregular spiral threads which number about fifteen between the spire sutures; they are finer on the base; growth-lines sinuous and belong to Class 4 of Guillaume’s classification; they have a broad, shallow, sinal curve centering in the lower half or widest part of the whorl; aperture circular. Length, 42 mm.; diameter, 16 mm. Remarks—This Turritella was collected in the Lower Zorri- tos of Quebrada Higueron near Rica Playa. Similar to imfra- carinata in general form, it differs by its non-carinate whorls and finer spirals. The shell figured by Spieker as T. nelsoni var. ro- tundata Grzybowski (not true rotundata of Grzybowski) is some- what similar but has more evenly rounded whorls and different spiral sculpturing. Locality and Geologic Occurrence.—Lower Zorritos of Que. Higueron near Rica Playa. Turritella infracarinata Grzybowski Plate 22, fig. 8 Turritella suturalis Nelson, 1870, Trans. Conn. Acad., vol, 2, p. 188. (not of Sowerby and Philips. aced to Spieker). Turritella infracarinata Grzybowski, 1899, Neues Jahrb. f. Min. etc., Beil. Bd. 12, p. 643, pl. 20, f. 5. Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 79, pl. 3, figs. 9, 10. 7 22 Woods, 1922, Bosworth, Geology of North- West Peru, p. 109, pl. 18, figs. 2, 3. 5))s) 99 ae. ae Steinmann, 1929, Geologié von Pert, p. 200, fio. 247. Turritella infracarinata var. zorritensis Spieker, 1922, op. cit., p. 80, joi, By, iiez, TL - Turritella rotundata Grzybowski, 1899, op. cit., p. 643, pl. 20, f. 6. Turritella nelsom Spieker, 1922, op. cit., p. 74, pl. 3, figs. 5, 6. (new name for suturalis Nelson). Turritella nelsom var. truillissatia Spieker, 1922, op. cit., p. 78, pl. 3, fig. 8. Original description—Umeginge dachférmig abfallend, in 4% der Hohe gekielt, von da gegen die Naht verschmilert. Sie tragen 8 Spiralrippen, von denen die dritte von unten, die auch den Kiel bildet, am stirksten ist. Die anderen verlaufen gleichmiassig in gleichen Zwischenraumen. Zwischen den 5 unteren sind noch feine lneare Spiralstreifchen wahrnehmbar. Lange 95 mm., Breite bei der Miindung 23 mm. In ihrer ganzen Beschaffenheit zeigt sie sehr viel Ahnlichkeit mit T. swhangulata Broce. (vergl. Sacco 1. ¢.). —Grzybowski, 1899, Remarks.—Grzybowski and Spieker have unduly multiplied the nominal forms of this common and characteristic Zorritos 197 OLSSON: PERUVIAN MIOCENE 197 species. Its earliest name of suturalis of Nelson, being preoc- cupied it was changed to nelsoni by Spieker although Grzybowsk1 had described the same species as imfracarinata. The largest specimen measured by Nelson is the shell figured by Spieker as fig. 6 on Plate 3 and may be chosen the lectotype of suturalis and nelsoni. Spieker’s figure 5 was also drawn from a specimen in the Nelson collection. Grzybowski’s rotundata and infracarin- ata described in 1899 represent the same species. Since infra- carinata is the most common and characteristic form, this name is used instead of rotundata described earlier on the same page. Spieker’s varieties of zorritensis and truillissatia are based on slight difference in spiral sculpture and have no real status as separate forms in a large series. The carination of the whorls which suggested the name infra- carinata or an overhanging of the lower part of each whorl over the following turn, is variable but nearly all specimens show this feature to a greater or less degree. Grzybowski’s rotundata is an old, mature shell but even in this form the whorls are not evenly convex but broader about the lower half. Spieker’s ro- tundata is possibly a different species. The whorls are generally sculptured with strong, primary spiral threads separated by wide interspaces which often contain a single, smaller, secondary thread otherwise the interspaces are smooth or sculptured simply with growth-lines. The growth-lines belong to Guillaume’s Class 4. Turritella wittichi Hertlein and Jordan’? needs comparison with this species. Locality and Geologic Occurrence-——Upper Zorritos forma- tion, Zorritos, Punta Picos, etc. Variegated bed, Punta Picos. Cardalitos formation, Caleto Grau. Montera formation, near Que. Montera. Turritella inca Grzybowski Turritella inca Grzybowski, 1899, Neues Jahrb. f. Min. ete., Beil. Band. 12, p. 644, pl. 20, fig. 1. 42 »? Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 73. Turritella inca, var. trita Spieker, 1922, op. cit., p. 73, pl. 3, fig. 4. Original description—Umiinge convex, etwas zweikantig. Die 4 unter- 152Hertlein and Jordan, Proc. Cal. Acad. Nat. Sci., 4th series, vol. 19, pl. 21, figs. 3, 4. 198 BULLETIN 68 198 sten Spiralleistchen sehr schwach angedeutet, dicht beieinander legend, die fiinfte und siebente Rippe sind die stirksten; sie bilden 2 Kanten, die ein flaches, in der Mitte mit schwacher Leiste versehenes Band umgrenzen. Es folgen gegen oben noch 5 ziemlich starke, gleiche Spiralleisten. Die Hohe des der Spitze entbehrenden Bruchstiiekes 90 mm, Dicke an der Miindung 22 mm, oben 6 mm. Die totale Liinge méchte bis 115 mm. be- tragen._Grzybows ski, 1899. Remarks.—This Turritella is not known to me. It is charac- terized by its banded sculpture, the two principal spirals form- ing a wide band around the lower half of the spire-whorls such as occurs in Turritella gatunensis but is much larger and evi- dently related to infracarinata. Spieker’s trita is probably the same species. Locality and Geologic Occurrence.—Zorritos formation, Zor- ritos (Grzybowski), Que del Toro (Spieker). Turritella bifastigata Nelson Turracella bifastigata Nelson, 1870, Trans. Conn. Acad., vol. 2, p. 189. aH Spieker, 1922, Johns Hopkins University, Studies in Geology, IN@s By jo OB, Jol, 3B, ine, IL, ue 1 Hodson, 1926, Bulls. Amer. Pal., vol. 11, p. 2118, Wl GW); ite, ale Turritella gothica Grzybowski, 1899, Neues Jahrb. f, Min., etc., Beil. Bd. 12, p. 645, pl. 20, fig. 10. Original description.—Shell turreted, slender; whorls twelve to sixteen, flat or slightly coneave, except the body whorl, which is regularly convex; whorls bordered on each side by a strong, obtuse ridge. Intermediate spaces ornamented by fine raised, nearly equidistant, re- volving lines, about ten in the space of five millimeters. Sutures small and narrow, or rendered indistinct by the development of the bordering ridges. Body whorl somewhat convex, except in young shells; strongly wrinkled by the lines of growth, which on well preserved specimens, are sharp and acute. Base of this whorl marked by from seven to ten lines, nearly as strong as the ridges of the upper whorls. Aperture rounded; outer lip thin and slightly produced below. A specimen consisting of seven lower whorls gives the following measurements: length, 61 millim.; breadth, 19.1 millim.; breadth of upper whorl, 7 millim. Nine whorls from a younger specimen give: length, 39.95 millim.; breadth, 10.6 millim.; breadth of upper whorl, 3.2 millim.—WNelson, 1870. Remarks.—This species is de Gicnal by its flat to slightly concave whorls with a cord-like ridge of varying strength bor- dering each suture, the upper one usually the stronger. Hodson, who has examined Nelson’s specimens, selected the largest one measured by Nelson as the lectotype. This is the specimen fig- ured by Spieker. It has also been refigured by Hodson. Several closely related Turritellas of the bifastigata group, occur in the Caribbean Miocene. The value of some of the names 199 Otsson: PERUVIAN MtrocEenr 19% proposed for these forms is uncertain as comparative material, ismeager. Turritella cartagenensis Pilsbry and Brown from Col- ombia seems sufficiently different from typical bifastigata to rep- resent a separate species. Typical cartagenensis is a large, finely sculptured form with a rapid taper and small swelling about the upper suture. Hodson’s democraciana may be a varietal form of cartagenensis rather than bifastagata. Turritella oreo- doxa Olsson is probably a variety of bifastigata and is character- ized by its pronounced posterior swelling. The material of this form consists of two fragmentary specimens and the sculpturing of the base is unknown. Turritella bifastigata var. maracaibensis differs from fastigata sensu stricto by its finely sculptured base. This subspecies is rare in the Middle Miocene beds of northern Colombia. Locality and Geologic Occurrence-——Upper Zorritos forma- tion, Zorritos. Turritella varicosta Spieker Plate 22, fig. 5 Turritella filicincta var. varicosta Spieker, 1922, Johns Hopkins Uni- versity, Studies in Geology, No. 3, p. 66, pl. 3, fig. 3. Turritella filicincta varicosta Hanna and Israelsky, 1925, Proe. Calif. Acad. Sci., 4th series, vol. 14, p. 41, pl. 8, fig. 6. Original description.—This variety differs from 7. filicincta in having a larger number of primary ribs, irregularly arranged, and in having a some- what less prominent keel. One specimen only is in the collection, and it is somewhat worn, with the suosidiary sculpture not altogether clear; but it appears to agree with 7. filicincta in that respect, Its general relationships are similar to those of filicincta.—Spieker, 1922. Remarks.—Two broken, more or less worn specimens of a Turritella from the Variegated beds of Quebrada Heath, are re- ferred to Spieker’s varicosta. If they are correctly determined, varicosta represents a distinct species, differing from filicincta in having a larger, more solid shell, a more rapid taper and finer sculpture. The basal keel on our specimen is much lower than shown on Spieker’s figure. The species somewhat resembles 7. gomiostoma Valencienne but is easily distinguished by its sutural cord. Locality and Geologic Occurrence.—-Zorritos group, Upper Zorritos, Que. de Alturas (Spieker). Variegated beds. Que. Heath near Frenchman’s well. Zorritos form. Corona Park (Hanna and Israelsky). 200 BULLETIN 68 200 Turritella abrupta Spieker Turritella sp. ind. Nelson, 1870, Trans. Conn. Acad. Sci., vol, 2, p. 190. Turritella (Haustator) robusta Grzybowski, 1899, Neues Jahrb. f. Min. etc., Beil. Bd. 12, p. 646, pl. 20. fig. 3. (not Gabb, 1864). Turritella robusta Spieker, Johns Hopkins, University, Studies in Geology, No. 3, p. 84, pl. 4, fig. 5. Turritella robusta Woods, 1922, Bosworth Geology of North-West Rerun ps calO pla dS eetoee 4 sap ll O Ne tiong ill: Turritella robusta var. abrupta Spieker, 1922, op. cit., p. 85, pl. 4, fig. 6. Turritella charana Spieker, 1922, op. cit., p. 86, pl. 4, fig. 7. Turritella suwpraconcava Hanna and Israelsky, 1925, Proc. Calif. Acad. Sci., 4th series, vol. 14, p. 59 (new name for robusta Grzybowsk1). Turritella robusta var. fredeai Hodson, 1926, Bulls. Amer. Pal., vol. I 05 USB, fol, Gy rece I Bs joll, G, siles, Be Hoe iol OW, was, 1G, is ple Oiiora Mp le28. tosG: Turritella fredeai Anderson, 1929, Proce. Calif. Acad. Sci., 4th series, vol. 18, p. 119, pl. 17, fig. 1. Original description.—Es liegt mir ein nur aus, 2 Umgiange bestehendes Bruchstiich eines grossed Gehiuses vor. Die Umgiinge sind stark conisch, unten stark gekielt, zwischen dem Kiel und der flachen Naht coneav ein- geschniirt. Die Oberfliche tragt tiber dem Kiel 5, unter demselben I flache Leiste, Die Hohe der 2 unteren Umginge 45 mm., Breite unten 35 mm., oben 23 mm.; die totale Lange mag 140 mm. betragen.—G@rzybowski, 1899. Remarks.——This large, striking Twrritella is not common in Peru and our specimens being worn and broken, the reader is referred to Spieker and Woods for figures of the Peruvian form. The coiling follows along a sub-peripheral cord which forms the outer edge of a narrowed, platform-like base, usually sculp- tured with coarse spirals. (see Hodson, pl. 7, fig. 1). The growth- lines are well-figured by Hodson and Woods and belong to Class 4 of Guillaume’s classification. It does not have a well-marked sinus but rather a broad curve deepest across the keel, hence sloping forward across the upper face of the whorl to the upper suture. The Venezuelan and Colombian specimens separated by Hod- son as variety fredeai do not seem to differ sufficiently from abrupta to be recognizable and as shown in Wood’s figure, Peru- vian examples of robusta may become nearly as large as the Caribbean. Very large specimens or robusta have been seen in the Miocene deposits of Ecuador. Turritella bosei Hertlein and Jordan? may be the Lower 153Hertlein and Jordan, 1927, Proc. Calif. Acad. Sci., 4th series, vol. 16, p. 634, pl. 21, figs. 1, 2. 204 OLSSON: PERUVIAN MIocENE 201 Californian form of this species. According to Spieker, 7. abrupta (robusta) is closely related to the 7. ocoyana Conrad, and Wood- ring (Bull. G. S. A., vol. 40, p. 256.) has suggested that the tropi- cal forms may eventually prove to be only a subspecies of the Californian shell. 7. simplex Jenkins as figured by Martens from Java, seems to belong to this group. Figure 5 on Plate 4 of Spieker, is drawn from a specimen in .the Nelson collection. Locality and Geologic Occurrence.—Upper Zorritos forma- tion, Zorritos, Que. del Toro (Spieker). Cardalitos formation, Mal Paso. Turritella larensis bayovarensis n. subsp. Plate 22, figs. 4, 7, 10 Shell large, solid, habitus like “robusta” (abrupta) but with the coiling of the whorls just below the peripheral keel and not on a separate, sub-peripheral cord; the peripheral cord is strong and keel-like and usually with two or more small, spiral threads ; above the keel the face of the whorl is straight, flat but with the area bordering the upper suture contracted and sloping; the spiral sculpture is much weaker than in larensis, sensu stricto; there is a central band with three or four, primary spirals which are smooth or weakly beaded; very fine, tertiary threads cover the entire whorl; base slightly convex and sculptured with wrinkled tertiary spirals; growth-lines have a broad sinus be- tween the sutures and a shallow sinus on the base. Length, 56 mm.; diameter, 20.5 mm. (5 whorls). Length, 55 mm. ; diameter, 22.5 mm. (4 whorls). Length, 44 mm.; diameter, 31 mm. Remarks.—This large Turritella is probably distinct from larensis Hodson*** of Venezuela but in view of the variability of Hodson’s species, it seems best to consider the Bayovar shel as a subspecies, at least until a larger series is available for com- parative study. From the holotype of Jarensis, s. s. (Hodson, Pl. 3, fig. 5), the Peruvian form differs by its smaller keel, 154Hodson, 1926, Bulls. Amer. Pal., vol. 11, p. 180, pl. 3, figs. 1-5; pl. 4, figs. 1, 2, 4, 5; pl. 5, fig. 4. 202 BULLETIN 68 202 straighter sides and fine, weakly beaded spirals. The growth- lines are near Class 2 of Guillaume’s classification but have a shallow sinus across the base. Locality and Geologic Occurrence-——Montera formation, Bayovar. : Turritella illesca, n. sp. Plate 22, figs. 1, 2 Shell large, solid, with coarsely sculptured whorls and moder- ate taper; nucleus unknown; post-nuclear whorls 12 or more, convex, the sutures close, bordered by the sloping or excavated margin of the adjacent whorls; the sculpture of the spire-whorls is formed by 3, strong, spiral cords or ridges separated by wide, concave spaces; the uppermost or posterior ridge is the strong- est and separated from the 2 lower, by a deeper, spiral groove; the 2 lower ridges are somewhat closer together, the lowest be- ing a little stronger and keel-like, the interval between them is shallower than the space above; the growth-lines sinuous with a deep sinus in the middle of each spire-whorl and a shallower sinus across the base; fine spirals cover the lower ridge and prob- ably the whole whorl but the face of the whorl is coarsely wrinkled by the growth-lines ; base somewhat convex and marked with obscure spirals. Length, 90 mm.; diameter, 28.5 mm. (12 whorls). Length, 68 mm.; diameter, 28.5 mm. (5 whorls). Remarks.—This is a peculiar and striking species, quite un- like any described recent or fossil form. The convex whorls and strong spiral ridges recalls Turritella (Zaria) duwplicata Linné. Locality and Geologic Occurrence.-—Montera formation, Bayovar at Tric Trac Point. Turritella altilira Conrad, subsp. Plate 28, figs. 3, 4 Turritella altilirata Grzybowski, 1899, Rares Jahrb. f. Min., Beil. Bd. 12, p. 645, pl. 20, fig. 7. Turritella sp., ef. altilira Woods 1922, Bosworth, Geoloes! of North- West Peru, p- 110, pl. 19) figs. 2-4. Turritella altilira Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 59, pl. 2, fig. 12. Remarks.—TVhis Turritella is common in the Cardalitos shales and is probably confined to these beds or at least very rare at other horizons in the Zorritos region. The shell is solid, very long 203 OLSSON: PERUVIAN MIOCENE 203 and slender and usually only fragments of the later whorls are found. The two spiral cords or ridges are large, coarse and generally not strongly beaded. The upper one is simple as in altilira var. chiriquiensis Olsson from the Miocene of Panama. The central channel is sculptured with three or four, finely beaded spiral threads but the sutural area seems to be plain or carries only a low rib along which the whorl coils and which limits the base of the last turn. As most of the specimens are worn, the finer details and markings are difficult to determine. Among the Caribbean Turritellas of the altilira group, the Peruvian form seems nearest Twrritella vistana Hodson}? from Venezuela. Generally 7. vistana has stronger primary ridges with the central channel more deeply excavated. The better pre- served, slightly worn specimens of the Peruvian fossil may sometimes have spiral cords nearly as strong as those of the Venezuelan species. Since the earlier nepionic whorls are not preserved on any of our specimens, closer comparison is not possible at this time. Locality and Geologic Occurrence.—Cardalitos formation, Upper Que. Heath, Charan, Sechurita, Mal Paso. Turritella hubbardi Hodson Plate 23, figs. 1, 2 Turritella hubbardi Hodson, 1926, Bulls. Amer. Pal., vol. 11, p. 14, pl. 7, figs. 2-5; pl. 8, figs. 1-6; pl. 9, figs. 1, 5, 6. Turritella hubbardi Olsson, 1931, Bulls. Amer. Pal. vol. 17, p. 172, pl. 12, figs. 4, 6, 8, 10, 13, 14, This species was first described by Hodson from Venezuela. It was subsequently discovered in the Peruvian Oligocene in both the Mancora and basal Heath formations, but the species is not common and always badly broken. The examples here figured as hubbardi were found associated with Bursa freya and Cardium stewardi in sandy beds, probably belonging to the upper Heath shales near Punta Bravo. They differ somewhat in details of sculpture from the Lower Heath specimens but the species is variable and in view of the poor preservation of the Peruvian material, it is doubtful that much value should be given to these differences. The lower cord is usually the strongest and forms a 155Hodson, 1926, Bulls. Amer. Pal., vol. 11, p. 46, pl. 28. figs. 3, 4; pl. 27, figs. 8, 9, 12; pl. 28, fig. 4. 204 BULLETIN 68 204 well-marked basal keel to the whorl. The second cord is fully as strong as the first on the early whorls but usually becomes reduced in size on the later turns. The spirals above the two anterior cords is fined and irregular in strength and spacing. Local.ty and Geologic Occurrence.—Probably Upper Heath shales along divide between Ques. Seca and Conchudo-Bravo. Turritella filicincta Grzybowski Turritella ( Haustator ) _ filicincta Grzybowski, 1899, Neues Jahrb f, Min. ete., Beil. Bd. 12, p. 645, pl. 20, fig. 2. Turritella (Haustator) Gabbiana Grzybowski, 1899, op. cit., p. 646, ply 20; figs aa: Turritella filicincta Spieker, 1922, Johns Hopkins University, Studies in Geology, No, 3, p. 65, pl. 3, fig. 2. Original description.—Es liegen mir mehrere Bruchstiicke vor, die samm- tlich der Spitzen entbehren. Die conischen Windungen sind dicht tiber der Naht mit scharf nach unten abgeschnittenem Kiel versehen. ; Die ganze Oberflache ist mit tiberaus feinen Spiralleistchen gezeichnet, die dicht beieinander liegen, Hs stehen deren 26 auf einem Raum von 5 mm. In dem oberen Theile der Windungen sind sie ziemlich gleich, in dem unteren dagegen liegt ein starkeres Leistchen zwischen 2 schwacheren, An der Basis verlaufen 4 Spiralrippen, die auch mit den feinen Leistchen be- deckt sind. Hohe des aus 5 Umgangen bestehenden Bruckstiickes 45 mm, Breite un- tem 20 mm, oben 10 mm; die totale Linge mag 80 mm betragen.—Grzy- bowski, 1899. Remarks.—T urritella filicincta 1s a characteristic species of the Cardalitos shales occurring in considerable numbers in upper Quebrada Heath and in the shales below the sandstones of Mal Paso. It is distinguished from bifastigata which it resembles, in the absence of the swelling or cord bordering the upper suture. The base of filicincta is strongly sculptured. Locality and Geologic Occurrence.—Cardalitos formation, up- per Que. Heath, Mal Paso, etc. Turritella broderipiana alturana Spieker Plate 23, fig. 11 Turritella plana Nelson, 1870, Trans. Conn. Acad. Sei. vol. 2, p. 188; not of McCoy, nor of Brinkhorst 1861 (aced. Spieker). Turritella alturana Spieker, 1922, Johns Hopkins University, Studies in Geology, No. 3, p. 62, pl. 2, fig. 13. Original description.—Shell elongated, turreted, with from 13 to 19 (?) nearly flat whorls, gradually tapering to a point. Whorls flat above, slightly convex below, marked by fine, equal revolving lines 20 to 25 in the space of 5 millim, Sutures deeply impressed and broad. Two lower whorls much more convex than the upper ones; revolving lines stronger and crossed by distinct lines of growth. I have not seen a perfect specimen of this very interesting species, and hence measurements and the number of whorls can only be given approx- imately. A specimen consisting of the 8 lower whorls gives the following measurements: length 117.4 millim.; breadth 34.6 millim; breadth of the 205 OLSSON: PERUVIAN MrocENE 205 upper whorl 13.4 millim. A fragment belonging apparently to the same specimen gives for the length of the upper seven whorl 35 millim.—wNelson 1870. Remarks.—There are five specimens of this Twrritella in our collection from Tucillal. The largest and most complete has eight whorls and measures 81 millimeters. Judging from Spieker’s figure, our specimens differ in being more slender and show a small swelling about the upper suture. The holotype of alturana (plana of Nelson) is in the Nelson collection at Yale. The specimen has eight whorls and measures about 117 milli- meters in length and is the large shell mentioned by Nelson. Spieker’s figure showing a perfect shell, is a restoration, the lower eight whorls belonging to the Holotype, while the tip and earlier spire whorls belong to the small shell mentioned by Nelson. Spieker considered altwrana as closely related to several Eo- cene species, particularly to 7. andersom Dickerson*’® from Cal- ifornia. Dickerson’s figure of anderson shows a shell with flat whorls very similar to altwrana but it is extremely doubtful that the two species are at all related. The growth-lines are not well indicated on Dickerson’s figure but appear to have the deep medial sinus of the regular Eocene Turritellas belonging to Guil- laume’s Class 1 and 2. The growth-lines of altwrana belong to Guillame’s Class 4 which Guillaume has shown, does not appear earlier than the lower Miocene. Altwrana is however so closely related to the common West Coast Turritella broderipiana d’Orbigny that it is doubtful that the fossil can be separated solely on conchological grounds. Turritella broderipiana is quite variable. The shell is usually very slender, the whorls being flat and lying in the same plan or they may have a pronounced swelling about the posterior suture. In Tryon’s Manual of Conchology, broderipiana and banksu Reeve are lumped with goniostoma Valencaennes and this same course is followed by Dall (Peruvian Check List p. 292) and by Carpenter (Mazat- lan Catalogue p. 330). Actually the three forms are very dis- tinct and although having the same geographic distribution, there are no intergrading members, Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal at Zorritos. 156Dickerson 1916, Univ. of Calif., Bulls. Dept. Geology, vol. 9, p. 501, pl. 42, figs. 9a, 9b. 206 BULLETIN 68 206 Turritella gonisotoma Valenciennes, var. Plate 23, fig. 10 ef. Turritella goniostoma Valenciennes 1833, Humboldt Voyage., Zool., vol. 2, p, 275. ef. Turritella goniostoma Reeve, 1849, Conch. Icon., Twrritella, figs. Git finsetane goniostoma Steinmann, 1929, Geologie von Peru, p, 257, fig. 263. A single specimen of this Turritella was found at Tucillal as- sociated with altwrana. From young specimens of goniostoma of the same size, the Tucillal shell differs by its deeper sutures but this difference has probably been accentuated by weathering. The earliest whorls have the central spiral somewhat stronger than the others so that the whorl is weakly angled about the mid- dle. The early spire-whorls of recent goniostoma are similar but in the smaller banksw the primary spirals persists through the entire life cycle. Its rapid taper and stronger spiral sculpture, easily separates this species from altwrana Spieker. Our collection from Tucillal also contains the apical portion of a small Turritella with bi-angled whorls. This form may be related to banksu but the preservation is too poor for certain identification. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Family NATICIDAE Genus NATICA Scopoli Subgenus NATICARIUS Dumeril Natica near canrena Linné or unifasciata Lamarck Shell small, solid, with a large, convex body-whorl and short, erect spire; nucleus consisting of 2.5 smooth whorls; post-nu- clear whorls of 2.25 turns, rapidly increasing in size; sutures close, distinct and bordered by strong, almost tangentially in- clined, and retractive, curved lines or grooves, extending about half way to the middle of the body-whorl; rest of the surface smooth or marked only by fine, irregular lines of growth; um- bilicus deep with a large, funicular rib, emerging near the base of the umbilicus and separated from the umbilical wall by a deep groove; aperture semilunar, the parietal wall with a thick callus ; outer lip of medium thinness, oblique. Height, 15 mm.; greater diameter, 14.5 mm. 207 OLSSON: PERUVIAN M10cENE 207 Remarks.—Five specimens of this small naticid are in our collection from the Lower Zorritos of Zapotal and Santa Cruz. They resemble small shells of Natica canrena and unifasciata. Faint revolving lines may be seen on one specimen from Santa Cruz like those of the Stigmaulax group, while the other Santa Cruz specimen is perfectly smooth. From small recent speci- mens of canrena and unifasciata, they differ by their stronger, tangential plicae but except in size, appear very near to Gatun and Colombian shells identified as canrena. Possibly Cossmann’s antinacca or Hodson’s name of precanrena should be used for the fossil forms of canrena but in view of their great likeness, their ultimate classification most await the discovery and de- scription of the operculum. The Peruvian fossils are uniformly small and are probably mature. N. guppyana Toula from the Miocene of Panama, Costa Rica and northern Colombia, is usually referred to Stigmaulax Morch (genotype N sulcata (Born) although lacking except very faintly, the spiral lines of sulcata and its Bowden form vererugosum of Cossmann. The operculum of guppyana does not appear to be known. The sculpture of guppyana is very variable, the shells frequently becoming smooth when adult. These smooth shells resemble canrena but may be distinguished by their more strongly sculptured spire-whorls and _ widely spaced, incised lines or grooves are usually persistant on the um- bilical wall. N. broderipiana Recluz is a recent representative of guppyana in the Pacific fauna along the coast of northern Peru and Ecuador. Young shell of broderipiana are nearly as strong- ly sculptured as typical guppyana but soon become smooth, with traces of the strong, incised, longitudinal lines persisting on the umbilical wall. A small Natica in the Tucillal material resembles a young unifasciata. The spire is higher, more slender with finer, tan- gential grooves along the suture. More certain identification cannot be made except from adult specimens. Locality and Geologic Occurrence-—Lower Zorritos of Que- brada Zapotal and Santa Cruz. Genus POLINICES Montfort Subgenus POLINICES s. s. Polinices (Polinices) coronis Hanna and Israelsky Plate 24, fig. 9 Natica coronis Hanna and Israelsky, 1925, Proce. Calif, Acad. Sei,, 4th 208 BULLETIN 68 208 series, vol. 14, p. 46, pl. 8, fig. 4. Original description.—Spire very high, composed of 5% whorls which are evenly rounded and symmetrical; umbilicus partially open; parietal wall covered with a greatly thickened callus deposit; suture not deeply im- pressed. Altitude 34 mm, (originally about 38 mm.); diameter 25 mm. Near the top of a small hill on the south side of Corona Peak, Peru.— Hanna and Israclsky, 1925. Shell of medium size, moderately solid, with a high spire; whorls about 5, between close, appressed, indistinct sutures; the whorls including those of the spire, are shouldered or obtusely angled about the middle, the area bordering the suture being flat- tened to slightly depressed; the body-whorl below the shoulder is also impressed so that its sides appear obliquely flattened ; aperture semi-lunar, the inner side straight; parietal callus large and thick, outer lip obliquely inclined; the umbilicus is deep and of moderate size with the pillar or columellar side thickened. Length, 23 mm.; diameter, 17 mm. Length, 24 mm.; diam- eter, 19.5 mm. Length, 27 mm.; diameter, 20 mm. Remarks.—P. coronis Hanna and Israelsky is quite common in the Peruvian Miocene as well as in Ecuador. The umbilical region is usually filled with matrix but the species is easily rec- ognized by its relatively high spire, its shouldered whorls and flat- tened body-whorl. In specimens showing the parietal callus, the small transverse groove seen on many species of Polinices seems to be absent. The parietal callus is large, passing below into the thickened, columellar wall. This may be the species recorded as subangulata by Spieker from the Variegated beds. Locality and Geologic Occurrence.—Zorritos group, Corona Peak (Hanna and Israelsky) ; Variegated beds of Que. Blanca; Montera formation, Que. Montero near Bayovar. Miocene beds along railroad between Amen and Playas, Ecuador. Polinices (Polinices) nelsoni, n. sp. : Plate 24, figs. 8, 10 Polinices subangulata Nelson in part, 1870, Trans. Conn. Acad., vol. 2, pl. 6, fig. 4., (not figures 12 and 13.) Shell small, solid, obliquely subovate in form; whorls about Ee rapidly enlarging and forming a small, obtuse spire; the body- whorl is large and forms the greater part of the shell; it is slightly impressed near the suture and also about the middle; sutures appressed; surface smooth, except for obliquely inclined, growth-lines ; aperture semi-lunar, about half as wide as long 209 OLSSON: PERUVIAN MI0cENE 209 and somewhat broader just below the middle; columellar lip straight, heavily callused above on the parietal wall, this callus carrying a small, transverse groove at the upper end of the um- bilicus; outer lip thin, oblique; the umbilicus is open and quite deep, usually with a small funicular rib entering from the thickened, columellar wall. Length, 17 mm.; diameter, 13.25 mm. Remarks.—This is a small species, somewhat like the West Indian P. lactea Guilding but more solid, with a higher, stubbier spire. The young shell figured by Nelson (figure 4) as the young of subangulata is probably this species. Young shells of subangulata do not differ greatly from the adult in form, the spire being lower, the body-whorl moderately flattened and cylin- drical in form while the umbilicus is smaller and more complete- ly covered with callus. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Polinices (Polinices) cf. uber Valenciennes There are two poorly preserved Polinices from Tucillal which are tentatively referred to this recent West Coast species. Com- pared with Reeve’s?’” figure of wher, our specimens seem to have a lower spire and somewhat larger and wider body-whorl. Pol- nices stanislas-meunieri Maury from Santo Domingo is higher and more slender with a narrower umbilicus. Locality and Geologic Occurrence —Tumbez formation, Que. Tucillal. Polinices (Polinices) subangulata Nelson Plate 24, figs. 1, 2 Polinices subangulata Nelson, 1870, Trans. Conn. Acad. Sei., vol. 2, p. 195, pl. 6, figs. 4, 12, 13. Polynices subangulata Spieker, 1922, Johns Hopkins University, Studies in Geology, No, 3, p. 87, pl. 4, fig. 8. Original description.—Shell varies from obliquely oval to sub-globular, moderately heavy and ventricose; spire short and pointed; whorls from six to seven, convex; body whorl large, nearly seven-eighths the length of the shell, convex, slightly produced anteriorly, broadest about one-fourth from top. From this point the whorl slopes, becoming very much flat- tened and presenting a marked angular appearance. Surface marked by distinct but irregular lines of growth. Sutures quite indistinct, except when the epidermis is slightly worn off. Aperture semi-lunar, half as wide as long, broadest a little below the middle. Outer lip sharp and thin. Columellar lip covered by a very thick callus, which rises into a more or less prominent ridge at the broadest part of the shell. Umbilicus small; 157Reeve, Conch. Icon., Natica, pl. 13, figs. 54a, 54b. 210 BULLETIN 68 210 in most specimens reduced to a mere chink by the callus, which is pro- longed below. Young, medium sized, and full grown specimens give the following measurements: First, length, 12.6 millim.; breadth, 9.4 millim. Second, length, 28.2 millim.; breadth, 22.2 millim. Third, length, 47.4 millim.; breadth, 39,2 millim.—Nelson, 1870. Remarks.—This species is very abundant in the Tucillal beds but we have not seen it from any other horizon. Spieker records subangulata from the Variegated beds but these records are questionable and probably refer to coronis Hanna and Israelsky. Polinices subangulata shows considerable variation. The typi- cal form as figured by Nelson and Spieker is a stubby shell with a low spire and almost shouldered whorls. The parietal callus is large, partly concealing the small, closely coiled umbilicus. In other shells, the spire may be quite high with feebly convex whorls and pointed apex. The umbilicus is usually small, some- times merely a narrow chink extending beneath the thickened callus of the columellar wall. The parietal callus is large, form- ing a thick, coarse deposit on the body-whorl and extending be- yond the plane of the aperture. The body-whorl is usually flat- tened medially so that its outline is quadrate to subcylindrical in form. Among recent West Coast Naticas, swbangulata is related to the group of Polinices panamensis Reeve and alveatus Troschel. Some of the recent examples of alveatus Troschel from Peru can scarcely be distinguished from subangulata. Generally the um- bilicus is somewhat more open amongst the recent shells but as in the fossils variation in this respect is considerable. Polinices panamensis is a much larger species with a larger umbilicus. Spieker compared subangulata with Maury’s stanislas-meuneri from the Miocene of San Domingo and Central America, but that species is not similar to this group. Mansfield!®* has recent- ly referred stanislas-meuneri to the new subgenus Dallitesta Mansfield. As previously noted®, subangulata is related to Polinices woodsi Olsson, a lower Upper Eocene species from the Lomitos conglomerate near Negritos. In woodsi, the parietal callus is much larger, almost concealing the umbilical area. Locality and Geologic Occurrence —Tumbez formation, Que. Tucillal at Zorritos. 158Mansfield, 1930, Fhorida State Geological Survey, Bull. No. 3, p. 124. 159Olsson, 1928, Bulls. Amer. Pale avolptap ao Ss 211 OLSSON: PERUVIAN MIOCENE 211 Subgenus NEVERITA Risso Polinices (Neverita) quirosana F. Hodson Policinices paraguanensis quirosana F. Hodson, 1927, Bulls. Amer. Jeti, Syl ANS\, Tos Wl, Goll, eke}, ampeys, al, A), A/c Polinices (Neverita) quirosana Olsson, 1931, Bulls. Amer. Pal., vol. 17, p. 165, pl. 11, figs. 4, 5, 8. For original and further description, see Hodson and Olsson’s papers referred to above. The Miocene specimens are somewhat larger than the forms from the Sal Chica and Punta Bravo grits but otherwise seem identical. As previously noted, quirosana is the Oligocene-Mio- cene representative of the Polinices duplicata group which is no longer living on the West Coast. It differs from the reclusiana group in the absence of the transverse groove on the umbilical callus. Locahty and Geologic Occurrence.—Zorritos formation, Que. Higueron. Polynices (Neverita) porcana Spieker Polynices porcana Spieker 1922, The Johns Hopkins University, Studies in Geology, No, 3, p. 88, pl. 4, fig. 9. Original description—Shell fairly large, heavy, the spire low and the apical angle somewhat broad. Whorls about five, well rounded and smooth excepting perceptible growth-wrinkles; sutures fairly distinct, not channelled. The last whorl of the spire is lower than in P. subangulata, and there is no shoulder. A heavy, bulbous callus surrounds the lower columella, merging into the peristome at its upper extremity, and _ ter- minating below in a rounded, bulb-like mass. There is no umbilical chink. Peristome, inner aperture, and base of columella broken away in all speci- mens available, but the aperture is undoubtedly somewhat narrow and oblique. Base rounded. Height, 34; maximum diameter (estimated) 35- 37.mm.—Spieker, 1922. Remarks.—This species is not in our collection. Spieker fig- ure shows only the base or umbilical view which are not suffi- cient for identification. Locality and Geologic Occurrence——Lower Zorritos forma- tion, between Quebrada Heath and Charan. Subgenus EUSPIRA Agassiz Polinices (Euspira) cf. dubius Recluz Plate 24, fig. 5 ef. Natica dubia Reecluz 1843, Proc. Zool. Soe., p. 209. ef. Natica dubia Reeve, Con, Icon., Natica fig. 41. Remarks.—A single specimen from Tucillal seems to belong to this recent West Coast species. It is a small form with a large convex body-whorl, low spire and deeply grooved umbili- cus. The parietal callus is fairly large but the columellar wall 1s 212 BULLETIN 68 212 generally free from callus except at its upper end. The aper- ture is semi-lunar and slightly spreading. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. Family CALYPTRAEIDAE Genus CRUCIBULUM Schumacher Subgenus CRUCIBULUM, s. s. Crucibulum (Crucibulum) ecuadorense, n. sp. Plate 24, fig. 11 Shell of medium size, costate, subovate, the height slightly more than half the length; apex distinct, somewhat posterior of the center and projecting or slightly curved over the side; the external sculpture consists of numerous, even riblets which in- crease through bifurcation or by intercalation of new ribs be- tween the earlier; the ribs are coarsely wrinkled and crowded, separated simply by grooves; interior unknown. Length, 23 mm.; diameter, 20.5 mm.; height, 16.5 mm. Remarks.—This species is recognized by its numerous, close and regular riblets. In recent imbricatum Sowerby, the ribs are fewer, coarse and separated by wide spaces. C. imbricatum al- though extremely variable in form, most shells are low, flattish, and the apex is low and blunt. In this species, the shell is mod- erately high with the apex slightly curved over the posterior side of the shell. Locality and Geologic Occurrence.—Lower Miocene exposed in cuts along railroad between Amen and Playas, Ecuador. Section Dispotaea (Say) Conrad Crucibulum (Dispotaea) inerme Nelson Plate 24, figs. 4, 7 Crucibulum inerme Nelson, 1870, Trans. Conn. Acad. Sci., vol. 2, p. 188. Original description.—Most of the specimens of this genus are also casts, but a fortunate break laid open the interior of one and showed the ‘‘eup’’ of a Crucibulum. The shell is oblong-oval, twice as long as high, and smooth externally, thus differing from all known species of the West Coast. The cup is large, semi-lunar, and apparently strongly attached to the shell along the whole of the convex side. On the free margin the cup is de- pressed, with a shallow sinus similar to that in C. spinosus Sby. The following are the approximate measurements: Shell, length 24 millim.; height 11.6 millim.; cup, length 13.4; height 8 millim.—Nelson 1922, Remarks.—There are two specimens in the Nelson collection at Yale. The smaller one which agree with Nelson’s measure- ments may be chosen as the lectotype. Both specimens are badly weathered with the surface detail completely destroyed and 213 OLsson: PERUVIAN MIOCENE 213 whether the shell was smooth as described by Nelson or other- wise sculptured cannot be determined from these specimens alone. The beaks are high, pointed and slightly recurved over the posterior side. A triangular break along the posterior side on both specimens probably marks the position of the internal cup, adhering widely along one side as in Dispotea. A specimens from the Upper Zorritos of Punta Picos may rep- resent inerme. The surface is smooth or simply sculptured with crowded, irregular growth-lines and faint, radial wrinkles on the right side. The beaks are not so high and pointed as in the types of imerme. Interior unknown. Dall?®° unites inerme with Crucibulum grande Say from the Chesapeake Miocene. Crucibulum inerme further resembles Crucibulum costatum Say as illustrated by specimens from Jones Wharf, Maryland'*. Crucibulum grande seems nearest but is typically much larger in size and more depressed while Cruct- bulum costatum from Jones Wharf is proportionally narrower in form and shows strong costations on the shorter side. Grzybowski’s Puncturella phrygia'® described from Grau has not been rediscovered. Judging by Grzybowski’s figures, it is not Crucibulum inerme as suggested by Woodring. A species of Puncturella has been described by Dall*® from the Bay of Pan- ama and the Galapagos Island. Locality and Geologic Occurrence-—Tumbez formation, Que. Tucillal (Zorritos) Nelson. Upper Zorritis of Punta Picos. Superfamily PTENOGLOSSA Family ARCHITECTONICIDAE Genus ARCHITECTONICA (“Bolten”) Roeding Subgenus ARCHITECTONICA, s. s. Architectonica (Architectonica) sexlinearis Nelson Plate 21, figs. 7, 10 a ee Solariwm sealineare Nelson, 1870, Trans. Conn. Acad., vol. 2, p. 194, joll, @, ime, Ik, Solarium sealineare Grzybowski, 1899, Neues Jahrb. f. Min. ete., Beil. Bd., 12, p. 642, pl. 20, fig. 13. Solarium sexlineare Woods, 1922, Bosworth, Geology of North-West Peru p. 109, pl. 18, figs. la, 1b, le. Original description.Shell circular, depressed; whorls seven to eight, 160Dall, 1892, Trans. Wagner Free Inst., vol. 3, pt. 2, p. 351. 161Martens, 1904, Maryland Geol. Survey, Miocene. p. 244, pl. 58, figs. 7a, 7 162G@rzybowski, 1899, Neues Jahrb. f. Min. Beil. Bd. 12, p. 642, pl. 20, figs. 112), dz. 163Dall 1908, Bull. Museum Comp. Zool., vol. 48, p. 353, pl. 4, figs. 10, 11, 214. BULLETIN 68 214 moderately convex, separated by distinctly marked sutures, ornamented by broad, subequal revolving lines. Body whorl large, two-thirds the height of the shell, marked with four revolving lines, of which that next the suture is the broadest, the remaining ones nearly equal in size. The line which forms the edge of the whorl is double the width of the others. Base marked by six revolving lines. First narrow, separated by deeply marked sutures. The next four form a series, narrowing towards the interior or um- bilical region. The last, forming the wall of the umbilicus is broad and deeply notched. Umbilicus widely open. Three specimen, only, of this species have been found, all slightly worn; it is. therefore impossible to state the superfical markings of the upper whorls. The species however, appears to have been notched transversely. Length 13.8 millim.; breadth 25.2 millim, This species resembles S. granulatum Lam., but that species has seven lines on the base of the body whorl, instead of six as in our spe- cies —WNelson, 1870. Remarks.—Vhere are three specimens of this species in the Nelson collection, the smallest and most perfect which is marked as the holotype, is the specimen figured by Nelson. A. sexlinea- ris seems to be a distinct species, easily distinguished from the nobilis group (granulata Lamarck) by its large, smooth, periph- eral cord while in nobilis, the peripheral cord is quite small so that the edge of the whorl is sharper and often overhanging. Woods figures of sexlinearis show this character well. The basal spirals as noted by Nelson, are fewer in number, more nearly equal in size and the spire is generally higher and more conical in form than usually seen in nobilis. The upper surface of the whorls have four spirals, the first spiral which borders the upper suture being larger than the other three. The surface of Nelson specimens are weathered but the spirals appear to have been smooth on the last turn. Two specimens from the Nelson collection measure as follows: Holotype, greater diameter, 25.00 mm.; height, 13.50 mm.; Paratype, greater diameter, 35.50 mm.; height, 18.50 mm. Locality and Geologic Occurrence-—Cardalitos formation, Que. Charan (Woods)., Upper Que. Heath., Mal Paso. Tumbez formation, Que. Tucillal, Zorritos, (Nelson). Architectonica sexlinearis corusca, n. subsp. Plate 21, figs. 5, 8, 9 Shell low, conic, solid, resembling A. sexlinearis but distin- guished in having the basal spirals, six in number, strongly gran- ulated ; the peripheral cord as in sexlinearis, is broad and smooth so that the edge of the last whorl is obtuse or rounded; upper spiral cords four in number, the first lying next to the upper suture is much larger than the other three; the upper spirals 215 OLSSON: PERUVIAN MI0cENE 21 Or are strongly granulated becoming smooth on the last half or quarter turn on old shells. Greater diameter, 25.50 mm.; height, 13.50 mm. Remarks.—This variety is described from a well-preserved shell from the Miocene of Rio Betey in northern Costa Rica. The Peruvian shells referred to this variety are not well-pre- served or show only a part of the surface sculpturing. Corusca is distinguished from typical sexlinearis in having the basal spirals strongly granulated. The upper spirals are also granulated for a longer period, only becoming smooth on the last quarter or half turn on old shells. Typical sexlinearis is probably limited in its stratigraphic range to the Cardalitos and Tumbez deposits. Specimens from the Lower Zorritos of Que. Zapotal and the Lower Miocene of Se- chura have the basal spirals strongly granulated as in corusca. The Zapotal shell figured, differs slightly from the Costa Rican form in that the spiral cords are narrower and separated by wide grooves. Whether these differences are constant enough to consistently separate the Peruvian shells from the Costa Rican cannot be determined from the material at hand. The shells from Sechura are the same as those from Zapotal. Locality and Geologic Occwrrence.—Miocene of northern Costa Rica, Rio. Betey. (Holotype). Lower Zorritos formation, Que. Zapotal. Montera formation, Bayovar. Suborder PHIPIDOGLOSSA Family TURBINIDAE Genus TURBO Linné Subgenus CALLOPOMA Gray Turbo (Callopoma) belli Spieker Plate 24, figs. 3, 6 Callopoma lineatwm Nelson, 1870, Trans. Conn. Acad. Sei., vol. 2, p. 186, pl. 6, fig. 2; not Turbo lineatus of Da Costa, 1778 or of Lea, 1845 (ace. Spieker). Turbo belli Spieker, 1922, Johns Hopkins University, Studies in Ge- ology, No. 3, p. 91, pl. 4, fig. 11. Original description.—Shell turreted; spire elevated; whorls six (?), convex, Upper whorls slightly depressed in front, marked by a few, strong, subnodulous ridges, alternating with finer revolving lines, Body whorl very convex, marked above by two strong tubereulose ridges, and laterally and below by a few revolving lines, varying in size, as on the upper whorls, Whole surface marked by very fine and numerous lon- gitudinal lines, rather broader than the space between them. Aperture not observed, 216 BULLETIN 68 216 Length (4 whorls) 15.8 millim.; breadth 13.8 millim. This beautiful species, although quite distinct, closely resembles both Callopoma saxosum Wood and Callopoma fluctuoswnm Mawe. ‘From C. sawosum it may be distinguished by having the whorl less flat tened above; lacking the row of tubercles at top of the body whorl; and in having much finer and smoother longitudinal lines. From C. fluctuoswm it may be distinguished by lacking the strong rows of tubercles near the base of the body whorl; by having fewer revolving lines and stronger and more distinet longitudinal ones,—Nelson, 1870. Remarks.—I have no specimens of this species and for a fig- ure the reader is referred to Nelson and Spieker. ‘There are however, two Callopoma opercula among our Tucillal fossils which may belong to this species. According to Tryon’s fig- ures (Manual of Conchology, Turbinidae, pl. 59, figs. 30, 31), these opercula are very similar to those of saxosum. In the re- cent species, the central area is smaller and the first spiral rib counting from the center, is more strongly beaded and the peri- pheral cords seem a little more numerous. Direct comparison between specimens of a large series may show other characters or prove these to be of little systematic importance. Locality and Geologic Occurrence.—Tumbez formation, Que. Tucillal. EXPLANATION OF PLATES (Plates furnished, ready for insertion, by the author) 218 BULLETIN 68 218 HXXPLANATION OF PLATE 1 Figure Page I. o-Arcay (Senilia) cgaritensis; jn: (sp. 22 ee eee eee 15 Holotype, height 81.00 mm. Tumbez formation, La Garita 2. -Arca’ (Diluvarca) (colomba; n:) sp) eee 67 Holotype, length 56.00 mm. Cardalitos formation, Sechurita Area (Senilia) chiriquiensis toroensis Spieker 71 Length 63.00 mm. Variegated beds, Quebrada Picos Area (Senilia) chiriquiensis toroensis Spieker _..-.- (al Length 51.00 mm. Upper Zorritos, Que. La Cruz Arca (Senilia) chiriquiensis septifera. Grzybowski —.._—= 73 Height 46.00 mm. Upper Zorritos, Punta Picos Areca (Diluvarca) colomba, n. sp. —--—-----------------—---— eae were 67 Anterior end of Holotype. Diameter 48.00 mm. PALEONT. BULL. AMER. 19 il, Wolk, PIL, i 3 ae rhe si Seer 35273 as reese SShee PLATE II 220 BULLETIN 68 EXPLANATION OF PLATE 2 Figure 1. Area (Senilia) larkinii Nelson Topotype, length 68.00 mm. Tumbez formation, Que. Tucillal, Zorritos 2. Area (Diluvarea) spiekeri, n. sp. Paratype, length 19.50 mm. Lower Zorritos formation, Que. La Cruz, 3. Area (Diluvarea) spiekeri, n. sp. Paratype, length 15.00 mm. Que. La Cruz 4. Area (Senilia) larkinii Nelson : Interior of same specimen as figure 1 ih Aron, (Serb) irda IWeig@m 22 Topotype, length 55.00 mm. Que. Tucillal at Zorritos Ge At cae (Dil uiyair,@a}) ie Sp Te kena eee rag 1 eee Holotype, length 21.00 mm. Lower Zorritos formation, Que. La Cruz AN (Cumann) amie, ms S10 s * mires Lele Sees Paratype, length 19.50 mm. Lower Zorritos, Zapotal SuewAreay ((Cunearca)) (thaliiass ma (Spy ee ee Holotype, length 16.50 mm. Lower Zorritos, Que. La Cruz 9s Arcar (Cunearcas) it haliiay orice s [oq aera eee a ee Paratype, length 18.00 mm. Lower Zorritos, Que. La Cruz Page 75 65 65 15 15 65 BULL. AMER. PALEONT 3 nh Sets Seeeeee af. PLATE III 222 BULLETIN 68 222) EXPLANATION OF PLATE 3 Figure Page 1. Area (Noetia) reversa Sowerby, subsp. 2 SCOTT Length 80.00 mm. Tumbez formation, Que. Tucillal at Zorritos Be UNTO, [nereeniat SHON ee ye 83 Height of fragment 46.00 mm. Variegated beds, Zorritos 3. Ostrea (Lopha) haitensis Sowerby .-.-. -........-— 79 Width 76.00 mm. Montera formation, near Que. Montera 4. Chione (Anomalocardia) anomiana, n. sp. --. .-—— ------------------- 120 Holotype, length 34.00 mm. Variegated beds, near Zorritos 5. Corbula (Hexacorbula) cruziana, n. sp. — ee ee ne 141 Holotype, length 16.00 mm. Lower Zorritos, Zapotal GaaeAmomialDerbyils pleke 1s 83 Height 52.00 mm. Variegated beds of Que. Picos 7. Chione (Chionopsis) spiekeri, n. sp. —--—--—----—---------—-------------------- 117 Paratype, length of fragment 61.00 mm, Montera formation, Que Montera PG, 9 B5 Wolk Ne) BULL. AMER. PALEONT. INO r6S re To ee POs 5 ads jgetrentges ¢ poe ee le y 13088) , \ PLATE IV 224 BULLETIN 68 224 EXPLANATION OF PLATE 4 Figure Page 1. Areca (Diluvarca) sechurana, n. sp. —— ——..— Holotype, length 38.00 mm. Upper Zorritos formation, Punta Picos 2. Areca (Noetia) retractata Hanna and Israelsky —_- bee ee TO Topotype, length 41.00 mm. Upper Zorritos, Zorritos 38. Arca (Cunearca) zorritensis Spieker - —_~ CE eB ee a () Topotype, height 19.50 mm. : Tumbez formation, Que. Tucillal at Zorritos 4. sPecten:(Pecten)) ilesca;ns-spi eee 80 Paratype, height 19.00 mm. Montera formation, Que. Montera 5. Area (Cunearca) zorritensis Spieker Topotype, length 19.00 mm. Tumbez formation, Que. Tucillal at Zorritos Ne 70 Ga Becten CRecten)milles Cay rnin Spl ee eee ena ve pen es ue erm RIE TEE © () Paratype, height 18.25 mm. Montera formation, Que. Montera Ti I PectentnGEeceen) meal Les Casuarina eee tee etna nel ear TN CS () Holotype, height 18.00 mm. Que. Montera 8. Arca (Noetia) retractata Hanna and Israelsky Length 36.00 mm. Lower Zorritos, Zapotal meee af ((G) 9. Corbula (Hexacorbula) cruziana, n. sp. Paratype, length 13.50 mm. Lower Zorritos, Que. La Cruz 10. Pecten (Pecten) illesca, n. sp. So Sg ea ee AEN ID cea 80 Paratype, height 18.50 mm. Que. Montera 11. Arca (Cunearca) zorritensis Spieker Topotype Que. Tucillal at Zorritos 2 seectenw (eet en)) piles Casaar sets see 80 Paratype, height 17.00 mm. Que. Montera PIL, 4 Wolk, Wo BULL. AMER. PALEONT. NO: 168, Pl. 4 PLATE V 226 BULLETIN 68 226 EXPLANATION OF PLATE 5 Figure Page 1. *Pecten (Lyropecten) tucilla, n. sp. ek sy ein oe AU a cg pa ae gag SS Paratype, height 64.00 mm. Tumbez formation of Que. Tucillal at Zorritos 2. Pecten (Plagioctenium) woodringi Spieker — — _— IS reeset se 81 Holotype, height 23.00 mm. Nelson collection at Yale University 3. Pecten (Plagioctenium) ‘nelsoni; nm. sp. — 2 2 82 Holotype, height 41.00 mm. Tumbez formation, Que. Tucillal at Zorritos 4. *Pecten (Lyropecten) tucilla, n. sp. =. 2 ERED 83 Holotype, height 50.00 mm. Que. Tucillal at Zorritos 5. Pecten (Plagioctenium) woodringi Spieker SIS a ce ee OL Paratype, height 27.00 mm. Nelson collection at Yale University 6. Pecten (Plagioctenium) nelsoni, n. sp. sil sol i cas ae Se ee OO Paratype, height 36.00 mm. Que. Tucillal at Zorritos fi, Pecteny .(Pecten): illescay cm. 1sip 22 see ee i ek en Paratype, height 16.00 mm. Montera formation, Que. Montera, Sechura *After the printing of page 83 and the description of Pecten hopkinsi, this name was found to be preoccupied by Pecten hopkinsi d’Archiac Description des animaux fossilies du groupe nummulitique de l’Inde, p. 271. The name of the Peruvian species is here changed to Pecten tucilla. 5 NOP 68: BU. BULL. AMER. PALEONT 19 5, Wool, PIL, IS EEE PLATE VI 28 BULLETIN 68 3 228 EXPLANATION OF PLATE 6 Figure Page 1. Eucrassatella (Hybolophus) nelsoni Grzybowski —. 87 Length 51.00 mm. Cardalitos formation, Upper Que. Heath 2. Eucrassatella (Hybolophus) aviaguensis peruviana, n. subsp. 86 Holotype, length 41.00 mm. Montera formation, near Bayovar 3. Eucrassatella (Hybolophus) berryi Spieker 85 Length 25.00 mm. Lower Zorritos formation, Que. La Cruz 4. Eucrassatella (Hybolophus) nelsoni Grzybowski 87 Length 55.00 mm. Cardalitos formation, Upper Que. Heath be weinay trictractensiss cra Sys 25s ea eee a OE 91 Holotype, height 21.00 mm. Montera formation, near Bayovar 6. Eucrassatella (Hybolophus) gibbosa tucilla, n. subsp. _..- 88 Holotype, length 66.00 mm. Tumbez formation, Que. Tucillal at Zorritos Tis IMU 0 0 aah Ue SEB eB EN a 125 Length 40.00 mm. Variegated beds, Boca Pan 8. Eucrassatella (Hybolophus) berryi Spieker 85 Length 32.00 mm. Lower Zorritos, Que. La Cruz PIL ©, Wok IO BULL. AMER. PALEONT. NOMC8s PIs 6 We oie , Sear Sowa PLATE VII 230 BULLETIN 68 230 EXPLANATION OF PLATE 7 Figure Page 1. Lucina (Here) iduna, n. sp. Paratype, length 10.00 mm. Retouched photograph showing a small part of the lunule im- mersed into the hinge plate Montera formation, Que Montera bo Lucina trictracensis, n. sp. Paratype, length 22.00 mm. Montera formation, Trice Trac Point near Bayovar Leo ee eee O IL 3. Miltha pacifica, n. sp. Paratype, height 42.25 mm. Montera formation, Que. Montera 4, Miltha pacifica, n. sp. Se pee Sa R14 UO ee ers nee ee One SS Holotype, length 53.00 mm. Montera formation, Que. Montera Sa Mlthampaciticassnta sa eee ES UE oe Ah oed BE Uls ee at eee ee ee 93 Paratype, length 42.00 mm. Montera formation, Que. Montera 6. Loripinus (Pegophysema) sechura, n. sp. Holotype, length 35.00 mm. Montera formation, Que. Montera 7. Lucina (Illesca) andersoni Olsson eben lO 5 in a 2 Ce I 90 Height 8.00 mm. Retouched photograph showing the lunule entirely immersed into the hinge plate 8. Loripinus (Pegophysema) sechura, n. sp. — ~ Paratype, length 34.00 mm. Montera formation, Que. Montera PL. 7, Vol. 19 BULL. AMER. PALEONT. NO. 68, PL. 7 PLATE VIII 32 BULLETIN 68 232 EXPLANATION OF PLATE 8 Figure Page 1. Cardium (Dinocardium) ecuadoriale n. sp. Holotype, length 39.00 mm. Cuts along railroad between Amen and Playas 2. Lneina: (Here)! sidumiay 115.0 pices rn ee 89 Holotype, height 13.00 mm. Anterior view showing the sunken lunule Montera formation, Que. Montera 83. Cardium (Trigoniocardia) spiekeri Hanna and Israelsky —... 100 Topotype, length 16.00 mm. Tumbez formation, Que. Tucillal at Zorritos 4, Cardium (Trigoniocardia) hannai, n. sp. 99 Paratype, length 11.25 mm. Lower Zorritos, Que. La Cruz dae ucinan Ceres): vel uray ris iso e cee ree ec ee a 89 Paratype, length 13.00 mm. Montera formation, Que. Montera Ge. MG weirvay (CHE e)) ii ti clu ene ans (6S fo es ee Nal cet 89 Holotype, length 12.50 mm. Montera formation, Que Montera 7. Cardium (Trigoniocardia) spiekeri Hanna and Israelsky _...____ 99 Paratype, height 18.00 mm. Tumbez formation, Que. Tucillal at Zorritos 8. Cardium (Americardia) stewarti, n. sp. 101 Holotype, length 9.00 mm. Quebrada Seca and Conchudo-Bravo divide 9. Cardium (Trigoniocardia) hannai, n. sp. 99 Paratype, length 11.00 mm. Lower Zorritos, Que. La Cruz 10. Cardium (Trigoniocardia) hannai, n. sp. 99 Paratype, length 12.00 mm. Lower Zorritos, Que. La Cruz 11. Cardium (Trigoniocardia) hannai, n. sp. — 99 Holotype, length 11.50 mm. Lower Zorritos, Que. La Cruz 8 68, PL. NO. BULL. AMER. PALEONT. 19 8, Vol. PL aia Wane Ya ae i ee ai i ( tue stat oD erayavieing 2 f ANTS DAN ke hee nh as Oe Mei ns vy vs ih rata PLATE IX 234 BULLETIN 68 EXPLANATION OF PLATE 9 Figure i.) Dosinia:(Dosinidia) jillescas, n. (sp) = ee eee Holotype, length 63.00 mm. Montera formation near Trice Trae Point 2. Dosinia (Dosinidia) illesea, n. sp. ze Bi at ce Dorsal view of Holotype 38. Dosinia (Dosinidia) delicatissima Brown and Pilsbry —..- Length 45.50 mm. Lower Zorritos formation, Zapotal 4. Dosinia (Dosinidia) delicatissima Brown and Pilsbry —— ~~... Length 52.00 mm. From railroad cut between Amen and Playas, Ecuador 5. Dosinia (Dosinidia) delicatissima Brown and Pilsbry Height 53.00 mm. Same locality as figure 4 6. Pitaria (Lamelliconcha) aequicinecta Spieker — ~~ Internal cast. Length 53.00 mm. Upper Zorritos formation, Punta Picos 234 104 Le is) 68. NO. 19 BULL. AMER. PALEONT. 9, Vol. PL, 236 BULLETIN 68 EXPLANATION OF PLATE 10 Figure 1. Pitaria (Pitarella) tumbezana, n. sp. Holotype, length 42.00 mm. Cardalitos formation, Sechurita 2. Transennella herviderana Spieker Length 28.00 mm. Variegated, Que. Heath Pitaria (Pitarella) tumbezana, n. sp. Paratype, length 38.00 mm. Cardalitos formation, Sechurita (ee) 4. Chione (Chamelea) grzybowski, n. sp. Holotype, height 42.00 mm. Cardalitos formation, Que. Heath 5. Chione (Lirophora) grauensis, n. sp. Holotype, height 34.00 mm. Cardalitos formation, Que. Heath 6. Pitaria (Pitaria) sapotana, n. sp. Holotype, length 40.00 mm. Lower Zorritos, Zapotal 7. Chione (Chamelea) grzybowski, n. sp. Paratype, height 33.00 mm. Cardalitos formation, Upper Que. Heath 8. Chione (Chionopsis) cf. costaricensis Olsson Height 29.00 mm. Variegated beds of Que. Picos 236 PL. 10, Vol. 19 BULL. AMER. PALEONT. NO. 68, PL. 10 bo BULLETIN 68 EXPLANATION OF PLATE 11 Figure il, Pitaria (Hysteroconcha) humboldtiana, n. sp. Holotype, length 55.00 mm. 5 Tumbez formation of Que. Tucillal at Zorritos Chione (Chionopsis) propinqua Spieker — =. Length 22.50 mm. Lower Zorritos of Zapotal Chione (Chionopsis) propinqua Spieker .. Length 36.00 mm. Lower Zorritos of Zapotal Chione (Chionopsis) angelana Spieker Topotype, length 49.50 mm. Young specimen showing sculpture and smoothly weathered umbo ; Tumbez formation of Que. Tucillal at Zorritos Pitaria (Lamelliconcha) aequicincta Spieker — Internal cast. Length 39.00 mm. Upper Zorritos of Punta Picos Pitaria (Lamelliconcha) petersoni, n. sp. Holotype, length 38.25 mm. Lower Zorritos of Zapotal Pitaria (Lamelliconcha) aequicincta Spieker Length 45.00 mm. Upper Zorritos of Punta Picos Chione (Chionopsis) propinqua Spieker Length 37.00 mm. Lower Zorritos of Zapotal 238 Page 112 116 110 1] 68, PL. AMER. PALEONT. NO. BULL. its Wolk, We) PIL, 240 BULLETIN 68 240 EXPLANATION OF PLATE 12 Figure Page ls Chione (Chionopsis) variabilis Nelson ——-.-._--.-________________-__- 114 Height 82 mm. Tumbez formation, Que. Tucillal Chione (Chionopsis) variabilis Nelson —... eoeennely beans meme lH 7st Right valve showing the thin, concentric lleva Length 92 mm. Que. Tucillal Chione (Chionopsis) angelana Spieker —_- i oe 116 Right valve showing the perfectly smoot, “weathorod anmalb@ and Cardium-like internal ribbed structure Que. Tucillal Chione (Chionopsis) spiekeri, n. sp. ——---_--_----_----—----_----—-----— 117 Holotype, length 66 mm. 5 Sechura Chione (Chionopsis) spiekeri, n. sp. —-------------_---__- 117 Paratype, length 57 mm. Sechura PIL 12, Wri BULL AMER. PALEONT. NONGSse PE r lz 242 BULLETIN 68 EXPLANATION OF PLATE 13 Figure 1. Pseudomiltha (Zorrita) petersoni, n. sp. Holotype, length 68.00 mm. Cardalitos formation, Sechurita 2. Tellina (Eurytellina) amenensis, n. sp. —— Holotype, length 40.00 mm. Cuts along the railroad from Amen to Playas 3. Macoma (Psammacoma) zapotalensis Spieker —— _~ Topotype, length 68.50 mm. Lower Zorritos, Zapotal 4. Pseudomiltha (Zorrita) petersoni aquada, n. subsp. Holotype, length 115.00 mm. Cuts along the railroad from Amen to Playas 5. Iphigenia peruviana, n. sp. Holotype, length 30.50 mm. Zorritos group, Que. Charan 6. Panopea cf. coquimbensis d’Orbigny Length 89.00 mm. Cardalitos formation, Upper Que. Heath 7. Macoma (Psammacoma) zapotalensis Spieker Length 74.00 mm. Lower Zorritos, Zapotal 8. Tellina (Eurytellina) amenensis, n. sp. Paratype, length 37.00 mm. Cuts along the railroad between Amen and Playas 242 124 95 127 122 13 BULL. AMER. PALEONT. NO. 68, PL. Pil, Mae Wall PLATE XIV 244 BULLETIN 68 244 EXPLANATION OF PLATE 14 Figure Page 1. Harvella elegans tucilla, n. subsp. SUS SG Sa ee UL ree ee MLA Holotype, height 78.00 mm. Tumbez formation, Que. Tucillal at Zorritos 2. Corbula (Caryocorbula) nelsoni, n. sp. ie) Holotype, length 16.50 mm. Tumbez formation, Que. Tucillal at Zorritos 3. Corbula (Tenuicorbula) acutirostra zorritensis, n. subsp. — .. 144 Holotype, length 17.25. mm. Upper Zorritos formation, Que. Picos 4. Labiosa (Raeta) undulata gardnerae Spieker Raber ects aes eis SNe ta SY Length 43.00 mm. Variegated beds, Que. Picos 5. ‘Mactra (Micromactra) iridia, n. sp. 2S Se Se pee 28 Holotype, length 45.00 mm. Cuts along railroad between Amen and Playas 6. Mulinia zorritensis Nelson : ne Se Ohta Ae es ye eee 130 Topotype, length 21.00 mm. Tumbez formation, Que. Tucillal at Zorritos — 7. Corbula (Temucorbula) tenuis lupina, n. subsp. — Ea tLe 143 Paratype, length 16.25 mm. Tumbez formation, Que. Tucillal 8 Rellinay (buzytellina) ct) felixm Hanley.) 2-2 ae eee 123 Length 15.50 mm. Tumbez formation, Que. Tucillal at Zorritos 9. Corbula (Caryocerbula) nelsoni, n. sp. 5 3 139 Paratype, length 17.25 mm. Tumbez formation, Que. Tucillal at Zorritos 10. Corbula (Tenuicorbula) tenuis lupina, n..subsp. ss Ss«id1448 Holotype, length 18.00 mm. Tumbez formation, Que. Tucillal at Zorritos 11. Labiosa (Raeta) undulata Gould — Need ID Se ON Cee Abe Oe 131 Length 51.00 mm. Tumbez formation, Que. Tucillal at Zorritos Pie 14; Vol. 19 BULL. AMER. PALEONT. NO. 68, PL. 14 nee ani 4 Rea PLATE XV 246 BULLETIN 68 EXPLANATION OF PLATE 15 Figure 1. Terebra (Strioterebrum) ulloa, n. sp. — ~~ Holotype, length 33.00 mm. Lower Zorritos, Que. La Cruz 2. Terebra (Strioterebrum) ulloa, n. sp. Paratype, length 25.00 mm. Lower Zorritos, Que La Cruz 246 SBR et eee ee 147 3. Terebra (Strioterebrum) herviderana Spieker —.. Length 12.00 mm. Lower Zorritos Que. La Cruz 4. Terebra (Strioterebrum) tafalla, n. sp. —- Holotype, length 17.50 mm. Vaan R 5. Terebra (Strioterebrum) zapotalensis, is So = Holotype, length 14.00 mm. Lower Zorritos, Zapotal 6. Turricula (Pleurofusia) cruziana, n. sp. 150 Holotype, length 25.00 mm. Lower Zorritos, Que La Cruz 7. Terebra (Strioterebrum) herviderana Spieker Length 16.00 mm. Lower Zorritos, Que La Cruz 8. Terebra (Strioterebrum) pavonia, n. sp. _- = Bias Paratype, length 18.50 mm. Lower Zorritos, Que La Cruz 9. Terebra (Strioterebrum) pavonia, n. sp. Holotype, length 31.00 mm. Lower Zorritos, Que La Cruz 10. Turricula (Pleurofusia) cruziana, n. sp. _~ Paratype, length 22.00 mm. Lower Zorritos, Que. La Cruz 11. Cancellaria (Narona) trema, n. sp. Holotype, height 17.00 mm. Tumbez formation, Que. Tucillal at Zorritos 12. Cancellaria (Narona) trema, n. sp. Paratype, height 16.00 mm. Que. Tucillal at Zorritos Se epee 146 pase ee 150 PE lo: 68, BULL. AMER. PALEONT. NO. 15, Well, io PAE. PLATE XVI 248 BULLETIN 68 248 EXPLANATION OF PLATE 16 Figure Page 1. Conus (Dendroconus) bravoi Spieker —_-- Piatt Ea He are ne PE en 151 Height 50.00 mm. Montera formation, near Bayovar 2. Mitras(Mitra)) dunbari, nwsp. eee ee 166 Holotype, height 97.00 mm. Nelson collection at Yale University 3. Conus (Dendroconus) bravoi Spieker 151 Height 34.00 mm. Lower Zorritos, Que. La Cruz 4. Conus (Dendroconus) bravoi Spieker _.- 151 Height 50.00 mm. Montera formation, near Bayovar 5. Conus (Leptoconus) multiliratus spiekeri, n. subsp. 5S Paratype, height 16.00 mm. Lower Zorritos, Zapotal 6. Conus (Leptoconus) sophus, n. sp. — 154 Paratype, height 16.50 mm. Lower Zorritos, Que. La Cruz 7. Conus (Leptoconus) multiliratus spiekeri, n. subsp. 153 Holotype, height 14.00 mm. Lower Zorritos, Zapotal 8. Conus (Leptoconus) sophus, n. sp. ___-------—----------------—--------------- 154 Paratype, length 17.00 mm. Lower Zorritos, Que. La Cruz 9. Conus (Leptoconus) sophus, n. sp. —---—-------—-------- 154 Holotype, height 16.25 mm. Lower Zorritos, Que. La Cruz 10: Surcula nelsoni, ins Spy — 2 eee 150 Holotype, height 54.00 mm. Nelson collection at Yale University Le Olivellaye(Callllian’asxs) es Gayo 10 at sper one Sse 164 Holotype, height 8.50 mm. Lower Zorritos, Que. La Cruz 12) Olivellay (Callianax)) tapiras on) S)y ee ——————EEEE 164 Paratype, height 6.00 mm. Lower Zorritos, Que. La Cruz 16 68. PL. BULL. AMER. PALEONT. NO. 16, Vol. 19 ALS iby iti bese PLATE XVII 250 BULLETIN 68 250) EXPLANATION OF PLATE 17 Figure Page 1. Canecellaria (Pyruclia) spatiosa Nelson — 161 Lectotype, height 62.00 mm. Nelson collection at Yale University 2. Cancellaria (Pyruclia) spatiosa Nelson —...—--._________ 161 Paratype, height 50.00 mm. Nelson collection at Yale University 3. Cancellaria (———————) schucherti, n. sp... 162 Holotype, height 40.00 mm. Nelson collection at Yale University 4. Cancellaria (———————-) schucherti, n. sp. —-------—--------_--- 162 Paratype, height 37.00 mm. Nelson collection at Yale University Cancellaria (Euclia) larkinii Nelson ~~ 159 Paratype, height 39.00 mm. Nelson collection at Yale University 6. Cancellaria (Cancellaria) bradleyi Nelson —_-----~- 156 Lectotype, height 26.00 mm. Nelson collection at Yale University 7. Cancellaria (Euclia) larkinii Nelson — ~~ 159 Ventral view of the same specimen as figure 5 8. Cancellaria (Cancellaria) bradleyi Nelson ~~ — 156 Paratype, height 24.00 mm. Nelson collection at Yale University 17 Pie 68, NO. PALEONT. BULL. AMER. 19 7h, \Weole PIG. cet WW Wet PLATE XVIII 252 BULLETIN 68 25 bo EXPLANATION OF PLATE 18 Figure Page 1. Cancellaria (Euclia) triangularis Nelson Baier 2 Ste aaa ena 158 Holotype, height 25.00 mm. Nelson collection at Yale University 2. Cancellaria (Euclia) triangularis Nelson —- Bp ees es sare. Alits Holotype, height 25.00 mm. Same specimen as figure 1 3. Pseudolatirus tumbeziensis, n. sp. ... .. — EO eee sere seer 2 (4 51/ Holotype, height 34.00 mm. Lower Zorritos of Que. La Cruz 4. Phos (Antillophos ?) hodsoni, n. sp. — _- gis et are AR Nee Ios eee SAI 174 Paratype, height 30.00 mm. Lower Zorritos of Que. La Cruz 5. Pseudolatirus tumbeziensis, n. sp. — 167 Paratype, height 27.00 mm. Lower Zorritos of Que. La Cruz 6. Pseudolatirus tumbeziensis, n. sp. ——_- Ses opr RE eae ae ee 167 Paratype, height 25.00 mm. ; Lower Zorritos of Que. La Cruz I gel OS a 190 7. Strombina (Strombina) tumbezia, n. sp. Holotype, height 10.00 mm. Lower Zorritos of Que. La Cruz 8. Strombina (Strombina) lanceolata zorritosensis, n. subsp. —.......__ 191 Paratype, height 26.00 mm. Tumbez formation of Que. Tucillal at Zorritos Oe ri¢iariaxclezayen.sS pes tho tllusen te SSeS So eet 172 Holotype, height 9.15 mm. Lower Zorritos of Que. La Cruz LO), Dritiariay peru vilamay, Wy Spi eee ee re ee 171 Holotype, height 11.00 mm. Lower Zorritos of Que. La Cruz 11. Phos (Antillophos) woodringi, n. sp. —_.--------------- 173 Holotype, height 14.25 mm. Lower Zorritos of Zapotal 12. Phos (Antillophos ?) hodsoni, n. sp. sane o ans see 174 Holotype, height 31.00 mm. Lower Zorritos of Que. La Cruz 13. Strombina (Strombina) lanceolata zorritosensis, n. subsp, __...__ 191 Holotype, height 28.00 mm. Tumbez formation of Que. Tucillal at Zorritos 18 NOs GS ele BULL. AMER. PALEONT 18, Vol. 19 Pll eas, Dalia} ie il Preto Aer eae PLATE XIX 254 BULLETIN 68 254 EXPLANATION OF PLATE 19 Figure Page 1. Melongena colombiana Weisbord ol area Height 55.00 mm. Variegated beds of Que. Blanca 2. Cymia pilsbryi, n. sp. Holotype, length 48.00 mm. Lower Zorritos, Que. Higueron 3. Acanthiza (Chorus) voluta, n. sp. Paratype, height 23.00 mm. Basal Heath shales of Que. Zapotal ? 4. Melongena melongena consors Sowerby _.. .. _-- zs 176 Height 46.00 mm. Lower Zorritos, Que. La Cruz He ANS (Siar) LSA My Bio ae 178 Holotype, height 48.00 mm. Tumbez formation, Que. Tucillal at Zorritos 6. Acanthiza (Chorus) voluta, n. sp. Paratype, height 26.50 mm. Basal Heath shales of Que. Zapotal? 7. Acanthiza (Chorus) voluta, n. sp. 184 Holotype, height 32.00 mm. Basal Heath shales of Que. Zapotal? 19 NO. 68, PL. PALEONT. BULL. AMER. 19 Pky, WS Who} patie Ray Rs PLATE XX 256 BULLETIN 68 256 EXPLANATION OF PLATE 20 Figure Page 1. Buccinanops (Perunassa) zorritensis Nelson — ..-———“‘«W'OGSY Paratype, height 48.00 mm. Nelson collection, Yale University 2. Marginella (Egouana) incrassata Nelson Topotype, height 23.00 mm. Que. Tucillal at Zorritos 3. Northia guttifera Grzybowski Be a eee ae eee es ieee eee ov) Height 37.50 mm. Variegated beds, Que. Blanca 4. “Phos” phosoides Hanna and Israelsky RO lsd eee oe ee NS a 176 Length 35.00 mm. Montera formation, Bayovar 5. Buccinanops (Perunassa) zorritensis Nelson : z — i1@s) Paratype, height 48.00 mm. Dorsal view of same specimen as figure 1 6. Marginella (Egouana) incrassata Nelson —.. —..-- Ss«d1 65 Topotype, height 26.50 mm. Que. Tucillal at Zorritos 7. Acanthiza (Chorus) sula cruziana, n. subsp. —~ ~~. 185 Holotype, height 26.00 mm. Que. La Cruz 8. Potamides bocapanensis, n. sp. ----_----- eee SP Ie Dea ERE Ice PY 192 Holotype, height 28.00 mm. Variegated beds at Boca Pan. SeNorthila se ubbihe rays GixZyjo sys Katee eee ee ae 170 Height, 32.00 mm. Que. Blanca PL. 20, Vol. 19 . BULL. AMER. PALEONT. NO. 68, PL. 20 Feat apnhnt Tejon hat PLATE XXI 258 BULLETIN 68 EXPLANATION OF PLATE 21 Figure 1. Bursa (Crossata) ventricosa BO Ceri ps ave ee Se ape NA 10. Height 56.00 mm. Tumbez formation, Que. Tucillal at Zorritos Solenosteira (Fusinosteira) sechurana, n. sp. —------- Holotype, height 36.50 mm. Montera formation, near Bayovar Bursa (Marsupina) freya, n. sp. Holotype, height 22.50 mm. Divide between Que. Seca and Que. Conchudo-Bravo Bursa (@Varsupina)) freyas snes So ee Paratype, height 20.00 mm. Same locality as last Architectonica sexlinearis corusca, n. subsp. —-.---..--- Holotype, greater diameter 25.50 mm. Rio Betey, Costa Rica Bursa (Marsupina) freya, n. sp. —§ Ab an CORUING Da Paratype, height 21.00 mm. Divide between Que. Seca and Que. Conchudo-Bravo Architectonica sexlinearis Nelson —.... Holotype, greater diameter 25.00 mm. Nelson collection at Yale University Architectonica sexlinearis corusca, n. sp. 2... Holotype, basal view of the same specimen as figure 5 Architectonica sexlinearis corusca, n. subsp. Front view of Holotype Architectonica sexlinearis Nelson — LARD Sa ALREN o « R Front view of Holotype Nelson collection at Yale University 258 Page 186 180 187 187 214 187 213 214 214 Pit, il. Wolk, WwW) BULL. AMER. PALEONT. NO. 68. PL. 21 Tp A sane: Ra nll Da baer ane ec fad oa ih hee We. PLATE XXII BULLETIN 68 260 EXPLANATION OF PLATE 22 Figure Page bo on = 10. Turritella wWleseay one spar eee es 202 Holotype, length 90.00 mm. Montera formation, Tric Tae Point near Bayovar Turnritellla cies Cass Tiss (S Ps ee ee ie a wea ea eee 202 Paratype, length 68.00 mm. Tric Trac Point Turritellawhicay nm. spy bs. i eee ee eee 195 Holotype, length 42.00 mm. Lower Zorritos of Que. Higueron Turritella larensis bayovarensis, n. subsp. 201 Paratype, length 37.00 mm. Montera formation, Tric Trac Point near Bayovar Murnritellay yard COS tay) SCC yee eee een SEC 199 Length 43.00 mm. Variegated beds, Que. Heath ‘Misi imma CHPAVOONWSIS 2 2. 195 Length 87.00 mm. Montera formation, Que. Montera Turritella larensis bayovarensis, n. subsp. a ie eae A as ee See 220i Holotype, length 57.00 mm. Montera formation Tric Trac Point near Bayovar Ati) immecminein Civavioo ws 195 Length 61.00 mm. *Montera formation, Que. Montera Abiierert ial, HON, TG SD sa wf UN ae oe a ee 195 Paratype, length 29.00 mm. Lower Zorritos of Que. Higueron Turritella larensis bayovarensis, n. subsp. Paratype, length 56.00 mm. Tric Trac Point near Bayovar PIL, 22 coy | aN) BULL. AMER. PALEONT NO 163: Plt 22 st ia ma Te i vial PLATE XXIII 262 BULLETIN 68 EXPLANATION OF PLATE 23 Figure 1. Turritella hubbardi F. Hodson (Je) Ol 10. iLat, 12. Length of fragment 34.00 mm. Ques. Seca and Conchudo-Bravo Turritella hubbardi F. Hodson Length of fragment 23.00 mm. Same locality as last Turritella altilira Conrad, subsp. Length 40.00 mm. Cardalitos formation, Upper Que. Heath Turritella altilira Conrad, subsp. — - Length 42.00 mm. Cardalitos formation, Upper Que. Heath Potamides infraliratus Spieker Length 21.00 mm. Variegated beds, Boca Pan Turritella prenuncia cruziana, n. subsp. Paratype, length 35.00 mm. Lower Zorritos, Que, La Cruz Turritella prenuncia cruziana, n. subsp. Holotype, length 44.00 mm. Lower Zorritos, Que. La Cruz Turritella prenuncia Spieker 21 See nk Length 31.50 mm. Lower Zorritos, Que. La Cruz Turritella prenuncia Spieker _... __... _... Length 31.50 mm. Lower Zorritos, Que. La Cruz Turritella goniostoma Valenciennes var. Length 42.00 mm. Tumbez formation, Que. Tucillal at Zorritos Turritella broderipiana alturana Spieker __ Topotype, length 80.00 mm. Tumbez formation, Que. Tucillal at Zorritos Potamides infraliratus Spieker ~~ __ Length 19.00 mm. Variegated beds of Boca Pan 262 195 195 193 193 206 jPA Le 2) 68, NO. PALEONT. AMER. BUEE 2 Wok, i's) PIL, PLATE XXIV 264 BULLETIN 68 264 EXPLANATION OF PLATE 24 Figure Page 1. Polinices (Polinices) subangulata Nelson —_— Se ae 209 Topotype, height 40.00 mm. Tumbez formation of Que. Tucillal at Zorritos 2. Polinices (Polinices) subangulata Nelson — peste iter ee 209 Topotype, height 33.00 mm. Que. Tucillal at Zorritos Sie Purbor (EC allopornia) isp, fee a eS eee 215 Height or Vertical diameter 18.50 mm. Que. Tucillal at Zorritos 4. Crucibulum (Dispotaea) inerme Nelson —..- se YAW Diameter 23.00 mm. : Upper orritos, Punta Picos 5. Polinices (Euspira) cf. dubius Recluz _.... Er Sea eee he itelt Greater diameter 17.25 mm. Que. Tucillal at Zorritos 6. Turbo (Callopoma) sp. — ee re yl ee 215 Height or Vertical diameter 18.50 mm. Que. Tucillal at Zorritos 7. Crucibulum (Dispotaea) inerme Nelson — 212 Lectotype, length 24.00 mm. —. Nelson collection at Yale University Se olinicesm (Rolimices) MmeEls oni aS. a a 208 Paratype, height 17.00 mm. Tumbez formation of Que. Tucillal 9. Polinices (Polinices) coronis Hanna and Israelsky = BOT Height 23.00 mm. Variegated beds of Que. Blanca 10, IeMbiieas (embrbress)) meso, iio Gos — 208 Holotype, height 17.00 mm. Que. Tucillal at Zorritos 11. Crucibulum (Crucibulum) ecuadorense, n. sp. ~~~... 212 Holotype, length 23.00 mm. Cuts along Amen - Playas railroad 24 (Of), PAL. BULL. AMER. PALEONT. NO. 19 PL. 24, Vol. INDEX TO VOLUME 19 Light face figures refer to pages; heavy, to plates PN @EWOMARY sa ee solida 29 solida cruziana 23 VOU\bay geste eere seen Ee. Acknowledgements — he Amarillas sandstone _.... 16 Americardia Amiantis incrassata ovoidalis Ampullina ortoni eaieale Ampullinopsis spenceri —_ Anatina undulata _ ~ agin Andean geosyncline — Anderson, Frank 59 chiriquiensis 73 chiriquiensis mis chiriquiensis septifera_ 26 chiriquiensis toroensis— BS, 2G cholana 25 colomba 29 erescens dariensis 29 GIONEAWICOSID, fissicosta garitensis 32 obesifor- CENTUNMEINSIS GANGS ee tee eee THCATOONRODE), eee larkinii 20, 32 macdonaldi 17 19 modesta 14, 20 nelsoni nux obesiformis oronlensis pantheonensis cares retractata 4 14, 20, 23, 25, 26 reversa é : 3 32 sechurana Mee 3 4 26, 33 septifera 20 singewaldi Saree splekeri 2 23, 26 thalia a eR Se. eres LTA 9 23 toroensis ee toroensis crassa toroensis prolata tuberculosa valdiviana vanholsti 23 veatchi zapotalensis zorritensis : Seaalusy 4 381 zorritosensis 26 Architectonica ; sexlinearis oes 21 sexlinearis corusca 21 23, 29 Argobueccinum zorritense 169 Astarte dubia Asterodiscus Atrato valley B Bayovar formation 16 Berry, Prof. EK. W. 48, 60 Berry, Willard 35 Biocorbula a8 Bolivar geosyncline Bosworth, T. O. mene: ae Bouhtzo comb nee 135 265 Buccinanops Bo en es zorritensis —.—— = 20 31 Burckhardt —.——----- -------— TRUER) ee ae denentsist OR eet ae californica —-—...---—------= GUNA) gee oe chira yasila ----— ------- GEASS) eee Se freya ‘ ee ei proavus ee ae C Callianax z Calliostoma noduliferum Callopoma ' aes. Calyptraea -------— Ganal Zone ——=- —-—==-== Cancellaria —— ~~ === 4 balboae eee os Tyraclley 2 sees af bulbwlus === a 161 ‘ cassidiformis 158 S clavatula ‘ ellipsis © --——— es exopleura -—------ rs gabbiana —.--- 34 nf TaN ee et hettneri were islacolonis ------- ny leamstenv ies We larkinii) 2 17 Bal e montserratensis peruana : 23, 29 Y pyrum ——.---— ss rowelli sees - 23, 34 ee schelbele mes ss schucherti ------- 17 31 es Solid ae ef 160 f spatiosa —---—---—- 17 31 gS tesselatas == 5 OTN, eee U5) ‘ triangularis 18 ct tritonidea —------ f venezuela ---- 160 Cantharus distortus .—------— Cardalitos formation --------- 27 Cardium 22 - acuticostata --------- Y afinish 2 “ eeuadoriale --------—--—- 8 stewarti — subaucanum tenuimargo zorritensis 24 Caryocorbula Cerithium 6c grillanum --.---- 25 infranodatum . —--- 25 laevisculum cc 6c Chamelea Chapman, F. Charaos formation : Chicama structure Chile - - Chimu Andes Chione ee ie ae ae ee amathusia angelana —- 32 anomiana ——--------— 3 atlanticana eancellata compta costaricensis 25 gnidia grauensis 29 grzybowski 29 hendersoni 24 meridionalis paraquanensis 112, 113 propinqua 24 rowleli spiekeri 26, 34 succincta walli variablis 32, 111 Chionopsis 3 Chlamys Chorus Clavella solida Clavilithes (?) atahuallpai Clementia dariena 266 113 112 117 Talal 112 114 111 13 81 183 183 170 102 26, 32, 34 24, ‘ peruviana ‘ 6, Codakia 24 Columbella paytensis 14 turrita 23, 25, 27, 29, 34 bocapanensis Bl cacuminatus 31 molis bravoi multiliratus spiekeri __ williamgabbi 25), PHY Coquimbo beds 63 Corba eee ee 27, 136, 142 acutirostra zorritensis 27, 142 aequivalvis alabamensis biangulata bicarinata bradleyi BA, NBs bravoana 24, 185 buenavistana 6 14 cruziana 24 cubaniana fabiformis 24, 135 gatunensis glypta heterogenea hexacyma 136 lanceolata prenuncia 24; 135 [OURO POTATO, 25 radiatula 140 103 sulecata synarmostes 136, 140 talarana tenuis 136 tenuis lupina 32 14 wilcoxi 140 vicaria vieta viminea 140 Cordillera de la Costa __ . Coseinodiseus oculus iridis Courty Crassatella gibbosa _ Crassatellites charanensis _ nelsonil 2.2 2 ae pizarroi Cretaceous Crossata Crucibulum ecuadorense grande - COSC UIT eee Cryptomya californica Cuma alternata 181 Cuneocorbula Gyan So buchivacoana pilsbryi tectum Cypraea angustirima Cytherea affinis = planivieta 110 Dendroiconus Dentalium zone Deustua Diatomaceous earth 16, 35 Diluvarca Dinoecardium Discocyclina peruviana ___ Dispotaea Distorsio clathratus decussatus decussatus ringens 238, 44 g