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Repay he thd y e ‘ . ‘ i ‘ ‘ ‘ oe ' ee oe ivy ee tae ee Ce ee UAE di en ee PC he Se ce ce a ie as or thee ine vee ue ge ; ae wk Pre De Ae RO Ree Nt ane G78 The Fea HA Vea te werd gw ke, Pekar ai Y hb iw tay ae APR oy 7 - one . a meoy ye Ce Ce 2 re ee eee Oe en ee ty hehe l oe Por eer Cer Men Py Gly epee he > te “eo te ht 7 i. mea SCS One a oe ORT OE Shnesera ey ‘ A i re ot Ya ye heh guy rp deers ek Gh Se De Ce ; ORO Lea etetee coe bee MEO Hy ty) Pe a ruthsMUND WoopMaAN, W. D. MarrHew, CHARLES LANE Poor, WENDELL T. BusH Corresponding Secretary—HeENry KE. Crampton, American Museum Recording Secretary—Epmunp Otis Hovey, American Museum Treasurer—Henry L. DoHErty, 60 Wall Street Librarian—Raureu W. Towrr, American Museum Hditor—EpmMuND OtIs Hovey, American Museum SECTION OF GEOLOGY AND MINERALOGY Chairman—J. HE. WoopMAn, N. Y. University Secretary—CuHar es T. Kirx, Normal College (January—September) A. B. Pacint, 147 Varick Street (October—December) SECTION OF BIOLOGY Chairman—W. D. MarrHew, American Museum Secretary—Wi.L1i1AmM K. Grecory, American Museum SECTION OF ASTRONOMY, PHYSICS AND CHEMISTRY Chairman—CHarLEs LANE Poor, Columbia University Secretary—F. M. Prepvrrsen, College of the City of New York SECTION OF ANTHROPOLOGY AND PSYCHOLOGY Chairman—WENDELL T. Busy, 1 West 64th Street Secretary—Rosert H. Lowrie, American Museum 2 ed i Ae CONTENTS OF VOLUME XXIII Page Soo. EE seas Gad) Sn ee i a PE ray ccd ba cies, oie elets 6) sale cl wie i's. w sietpie slwiere Vil wees ave ii TEER As eefSiice SG) Bs Sa iii ates of Publication and Editions of Brochures: ............0.ccceeccece iii BUEN EMR Ty PANTER Teo ci tris) 6 c/ei cls <6 Social Os, 6 idiwlard 6 ath Sod 6 Seiad owe wu hvisvloee iv A Physiological Study of the Changes in Mustelus canis produced by Modi- fications in the Molecular Concentration of the External Medium. OE 2 CE IS a ag 1 Corrections and Additions to “List of Type Species of the Genera and Sub- genera of Formicide.’”’ By WILLIAM MorToN WHEELER............ 77 A Contribution to the Geology of the Wasatch Mountains, Utah. By Ferr- Meat Mtns inter ar (Plates T-V1). occ. ccc ae cede ec ewucwsce 85 Lockatong Formation of the Triassic of New Jersey and Pennsylvania. Pee RUS Se CE late (VER). oc os.. occ tic ees et twamac gees eens 145 Revision of the Genus Zaphrentis. By MARJoRIE O’CONNELL...........-.- Nee The Manhattan Schist of Southeastern New York State and its Associated Igneous Rocks. By CHARLES REINHARD FETTKE. (Plates VIII-XV) 193 mecorus OF Meetings, 1913. By EpMUND OTIs HOVEY.........0.-ccceeess 261 Pee AMIZAiOnN OL ENE! AGCAGEMY .. 2 66 5 ccc ok ale ec clae ele ce dsles vee wes ese 317 ene ret R a CNPP ROT fos oso na. ca so a 0 asia o'ere sias'e sb cpisleie ed Wedewls eo cee 317 OLE PEE COURIERS OG 2 OS Sal oe re ge eee eee ee 319 = DSL DET) (OST eSie 8 32 or A eee eee ere 320 SUS SUD, es a5g So ede 8 oe ee 323 Fay -FWS) oo) se ee ws oc cs RE EE ARTO NR RAE TE 324 een PAS at ecemoer, 1915. «6. os) cc's ve cw dinl's sole secu educawecd's 331 LEE scot Ste SOU de Sie 36 Se Pt et A Pe eae 343 DATES OF PUBLICATIONS AND EDITIONS OF THE BROCHURES Edition Pp. 1-75, 15 May, 1913 1200 copies Pp. 77-83, 29 May, 19138 1150 copies Pp. 85-143, 12 December, 1913 1400 copies Pp. 145-176, 27 January, 1914 1050 copies Pp. 177-192, 25 February, 1914 1300 copies Pp. 193-260, 30 April, 1914 1650 copies Pp. 261-353, 30 April, 1914 1000 copies iii LIST OF ILLUSTRATIONS Plates I.—A. Lower Half of South Fork Opposite Mill D. Big Cottonwood Can- yon, Looking North. B. Conglomerate at the Base of the Cambrian Quartzite in Little Cot- tonwood Canyon, Just Below Alta. II.—A. Photomicrograph of ‘“‘Tillite’ from the Head of South Fork. B. Photograph of Hand Specimen of “‘Tillite” from South Fork. III.—A. The Divide at the Head of South Fork and the Geologic Exposures of the South End of the Reade and Benson Ridge. B. Near View of the Upper Central Part of Fig. A. IV.—A. Alta Overthrust and Geologic Exposures on the North Slope of Little Cottonwood Canyon. B. Near View of the East-sloping Algonkian Quartzite shown on the Ridge of Fig. A. V.—Topographic Map of the Alta Region, Wasatch Mountains, Utah. VI— Geologic Map of the Alta Region, Wasatch Mountains, Utah. VII.—The Lockatong Formation [map]. VIlI.—Hornblende Schist and Epidosite. IX.—Pegmatite Dikes. X.—Manhattan Schist and Augen Gneiss. XI.—Specimens of Augen Gneiss. XII.—Photomicrographs of Gneiss, Schist and Granodiorite. XIII.—Photomicrographs of Schist. XIV.—Photomicrographs of Phyllite and Schist. XV.—Outline Map of Southeastern New York. Text Figures Change in A of blood of Mustelus due to immersion in fresh water until ut SRT OE sD ee Bee 6 8 wise asad ie my, u) w Siac a's 6 nd Hcl Be o\t biel’ w aja Sie v eweeeedees 15 Change in A of blood of Mustelus due to immersion of fish in a hypertonic TS gS ao ec i URE 0: 18 Relations of the A of blood to A of different solutions of sea-water....... 20 Respiratory movements in Mustelus 24 hours after destruction of spinal a tea al Ucn Ioics' 0) cee 2 eie'w 02d: d Glew Misia. se 4.e b's & eid +» ot eie.e luce 21 Changes in A of blood of Mustelus due to immersion in fresh water fol- ene TO TET MO SEM -VAELOL «6 <0. o cie oc ed cate nes ucleeebeleeeecueeeeae 23 Changes in the A of blood of Squalus due to transference from harbor STE ES UT ATICT 6 Se se US rcs eg 33 Diagram showing comparative A’s of blood of Mustelus in sea-water, N; in fresh water, F; and of saline solution, S, in which blood is first eS say SIEM 6 Ol te CI or 38 Showing the difference between the ratios of volume of corpuscles to plasma in normal blood, N, as compared with blood taken from fishes eet See hs OM ME ERESH WALOE, FRss sac wes eed vcdccclues ceancvcusess 38 Showing the hemolytic effect of different NaCl solutions on the erythro- cytes of four species of elasmobranchs and six species of teleosts..... 42 Showing changes in blood pressure of Mustelus canis due to immersion in een A The cere ete Sieroter gies! oer cto ectaiietle vy ois ciclelve. 6. sie ais o's dcalee's «sewn see 56 Showing the change in the character of the respirations during an hour ater immersion Of Mustelius in fresh. Water . ........:06 2 ; 1.87°:.. The average of these is 1.81°-+. The A’s of eighty specimens of Mustelus taken from the sea-water of the laboratory basin at various times proved to be as follows: TABLE I[.—Distribution of the freezing point of the blood of eighty specimens: of Mustelus canis mber Number of aia A of cui eis A of specimens 4 n Peel? 7 | re a 6 1.90 ° i ae Cee 7 1.84 4) 1-91 1 1.76 5 1.85 9 1.92 1 1.78 4 1.86 6 1.93 1 1:79 4 1.87 2 1.95 5 1.80 6 1.88 1 1.98 3 Sil 2 1.89 1 2.03 2 dn The mean depression of freezing point of the blood of the eighty speci- mens is 1.869°. Garrey recorded a mean value of 1.88°. But the mean A does not give a proper conception of the fluctuation in the osmotic pressure of the blood. It is possible that the extremes of this series repre- sent abnormal fishes. Greene (705) found a decrease of 32 per cent from the normal A of the blood of the Chinook salmon in the case of an old weak male and attributed this extreme variation to the pathological con- dition of the specimen. On referring to the above table, it will be seen that the greater number of A’s range between 1.80° and 1.93°. The dis- tribution of A’s between these points is, with the exception of those at 1.92°, quite uniform. The average A is just about midway between these two points. There are about as many A’s one side of the mean point as on the other side. The mean A of Mustelus blood is .05° lower than 8 ANNALS NEW YORK ACADEMY OF SCIENCES the sea-water in which it lives. It has already been noted that Rodier (700) observed the same fact in connection with the elasmobranchs at Arcachon. The observations of Bottazzi (706) reveal the same relation- ship. Finally, Garrey’s 705 data agree nearly with mine. The small difference between the A of the blood and that of sea-water is important in that the molecular concentration of the blood of elasmo- branchs is only approximately equal to that of the sea-water. According to the above table, the blood of Mustelus can pass with entire safety through a range of at least 0.15° in its osmotic pressure. CHANGES IN THE OSMOTIC PRESSURE OF THE BLOOD DUE TO ALTERATIONS IN THE DENSITY OF THE EXTERNAL MEDIUM PRELIMINARY STUDY It has been shown by a number of investigators that the osmotic pres- sure of the internal body fluids of the marine invertebrates depends upon the molecular concentration of the surrounding medium. Fredericq (704), Garrey (705) and Dakin (708) have shown that this is true to a certain degree of the elasmobranchs. Fredericq concluded that a new equilibrium was established when he put Scylliwm into diluted or con- centrated sea-water. For example, he put Scylliwm into diluted sea-water having a A of 1.67° for twenty-seven hours, at the end of which time the A of its blood serum was 1.70°. Another specimen was put into concen- trated water having a A of 2.%2° for twenty-four hours, when the A of the blood was 2.70°. Garrey (’95) found that the blood of Mustelus canis, though normally having a mean A of 1.88°, changed to 1.45° after an hour’s immersion in fresh water. Dakin (’08) found that when the spiked dog-fish, Acanthias vulgaris, and the skate, Raia clavata, were put into fresh water, there was a considerable fall in the osmotic pressure of the blood. The mean A of these forms was 1.90°. In the four hours dur- ing which the dog-fishes were in fresh water, the A of the blood changed to 1.435°, showing a rise in the freezing point of 0.465° from the normal- condition. The three specimens from which the above results were ob- tained were nearly dead at the end of the experiment. The change in the blood of the skate was not as great. This form was nearly dead at the end of two hours’ immersion in fresh water, at which time the A of the blood was 1.645°, showing a rise in the freezing point of .255°. In these experiments of Garrey and Dakin, death took place before a new osmotic equilibrium was established. I determined to ascertain whether there was any relation between the duration of immersion in modified solutions of sea-water and the change in the osmotic pressure of the blood. The form used was Mustelus canis. As brought into the laboratory, the fish SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS - 9 were placed in a large tank of sea-water. The salt water supply was then shut off and a stream of fresh water was turned into the tank. In a few minutes the water in the tank was fresh. After certain periods of im- mersion, the specimens were removed and a small quantity of blood was drawn from the caudal artery of each for a freezing point determination. It will be noted in the experiments that follow that the normal A of the blood of each animal is not given. But one freezing point determination was made in each case and that at the end of the time of immersion in the experimental medium. It should be borne in mind, however, that the mean A of the normal blood of Mustelus is about 1.87°. The results of the first experiment are as follows: | TaBLE II.—Change in the freezing point of the blood after various periods of immersion in fresh water (A of fresh water = 0.025 °) Immersion time in Specimen Fae i A of blood 1 35 162° 2 40 1.565 3 60 1.585 4 60 1.610 5 75 1.495 6 90 1.54 Individual changes in the freezing point of the blood are not the same for the same time of immersion. In a general way, however, the osmotic pressure becomes progressively less as the time of immersion increases. I next concluded to ascertain the relation of change in the freezing point of the blood to solutions less dilute than fresh water. In the second experiment a solution of one-half sea-water and one-half fresh water was employed. The A of this solution is about 0.90°. The results are as fol- lows: TABLE III.—Showing the change in the freezing point of the blood after various periods of immersion in one-half sea-water and one-half fresh water Immersion time in minutes Specimen A of blood t 50 Py a 2 75 1.705 3 100 1.685 4 200 1.595 9) 245 1.555 10 ANNALS NEW YORK ACADEMY OF SCIENCES In the third experiment a solution of three-fourths sea-water and one- fourth fresh water was used. ‘The following results were obtained. The A of this solution is about 1.35°. TABLE 1V.—Showing the change in the freezing point of the blood after various periods of immersion in three-fourths sea-water and one-fourth fresh water Immersion time in Specimen BREE Es 3 A of blood il 30 Waa ge 2 60 1.74 3 100 1.73 4 230 1.64 Both solutions cause a rise in the freezing point of the blood. Yet the rise is greater in the more dilute solution. On comparing the effects of the two solutions, it is seen that the same changes in the freezing point are produced in a shorter time in the second solution than in the third solution. A similar effect is produced in still less time in the first solu- tion, fresh water, than in the second one, which is one-half fresh water and one-half sea-water. The effect of concentrated solutions of sea-water was next measured. Two such solutions were employed: one with a specific gravity of 1.035 and a A of 2.60°; the other with a specific gravity of 1.040 and a A of 3.15°. The results were as follows: TABLE V.—Showing the change in the freezing point of the blood after various periods of immersion in concentrated solutions of sea-water Solution A—Sp. Gr. = 1.0385 A = 2.60° Immersion time in Specimen wiinnées A of blood 1 30 2.075° 2 50 2.115 3 7d 2.185 Solution B—Sp. Gr. = 1.040 A =3.15° Immersion time in minutes A, of blood Specimen 1 35 "2.10 ° 2 45 2.16 3 85 2.175 SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 11 In both of the solutions more concentrated than sea-water there is a lowering of the freezing point of the blood, an effect which is just the opposite of that produced by fresh and dilute solutions. The initial effect is greater in the more concentrated solution, although the final effect is about the same. Although in each of the five experiments the normal A of each speci- men as taken from sea-water is not known, the results indicate that the degree of change in the osmotic pressure of the blood depends upon the molecular concentration of the external medium. The results differ from those of Fredericq, in that they show that the osmotic pressure of the blood does not become equal to that of experimental media that differ markedly from the medium to which the animals are normally adapted. Attention is again called to the different degree to which the individual animals respond to modifications in the concentration of the external medium. Some die sooner than others in these abnormal media. Hyde (708) observed that the effects of operation varied in different skates. For example, Hyde noted that when the same operation was performed upon two animals apparently in every respect alike, in the one case the effects might be momentary, while in the other they might be severe and prolonged. CHANGES IN THE OSMOTIC PRESSURE OF THE BLOOD FROM THE NORMAL CONDITION UNTIL NEAR DEATH IN FRESH WATER AND CONCENTRATED SEA-WATER Green (705) found that the chinook salmon, Oncorhynchus tschaw- ytscha, in its migrations to the head waters of rivers for spawning, under- went a permanent decrease of 17.6 per cent in the concentration of its blood and yet was able to carry on with vigor the activities of its mus- cular and nervous system. How far may this decrease proceed before death takes place? He found that the blood serum of an old weak male salmon showed a decrease of 32 per cent from the mean A of the blood serum of normal salmon. This represents the maximum of dilution of which the blood is capable while still maintaining life. I concluded to investigate this question in the case of the dog-fish, Mustelus, and at the same time to study the progressive osmotic changes of the blood from normal life to death in fresh water and concentrated sea-water. Cessation of breathing was taken as an index of death. The following technique was employed: The spinal cord of the animal was exposed from the dorsal aspect, at the junction of the caudal fin with the trunk of the body. In this way no large blood vessel was interfered with. The cord was then destroyed by a probe as far forward as the an- 12 ANNALS NEW YORK ACADEMY OF SCIENCES terior dorsal fin. Hyde (’08) has shown that all the centers governing respiration in the skate, though of a segmental nature, are located in the medulla. Since in the above operation only the posterior two-thirds of the cord was destroyed, the nervous structures that govern respiration were not affected. ; After the cord was destroyed, the tail was removed, the caudal artery and vein being thus exposed. Blood was then taken for the determina- tion of its freezing point. After this, the caudal artery was closed with a small wooden plug covered with absorbent cotton. The animal with the exception of the posterior part of the body was then placed in the tank containing the experimental solution. After the desired time, a second sample of blood was taken for a second determination of its freezing point. The difference between the first and the second was a measure of the change in the osmotic pressure of the blood of the particular animal for the given time and the given solution. In a number of cases as many as six samples of blood, usually about 5 c.c¢. each, varying with the size of the fish, were taken from one specimen. The blood was drawn into a small beaker and placed in an ice bath until the caudal artery of the fish could be closed and the fish could be transferred back to the water. The common freezing tube with the side neck for the insertion of an ice erys- tal was not used on account of the large amount of blood that would thus be necessary for each determination. A test tube with a smaller diameter was used instead. Duplicate determinations of the freezing point of the blood and distilled water demonstrated that the error due to undercooling must have been small. The experiment was repeated in a number of cases with uniform results, as will be shown later. Several clean dry test tubes were kept at hand in order to facilitate the determination of the freezing point of a number of samples in the shortest space of time. I found that about fifteen minutes were required for all the steps in the making of a single determination. On account of necessary interrup- tions, it was not possible to make the time intervals equal in all cases. The whole blood, including corpuscles and plasma, was used in the ex- periments that follow. Hamburger (795), Roth (799) and others have asserted that the corpuscles are inert in determinations of the freezing point. Moore (’08) found that the corpuscles of pig’s blood had a A of from 0.02° to 0.03° lower than that of the serum. Since in all the fol- lowing experiments A was obtained in the way already indicated, the error due to the presence of corpuscles would be approximately constant in cases where the corpuscles were not laked. It would have been prac- tically impossible to make the frequent determinations of A in these ex- periments, had I stopped in each case to defibrinate and centrifuge each SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 13 sample of blood. The results are as useful for purposes of comparison as if the blood had first been defibrinated and then centrifuged. Time was saved by omitting these procedures and I believe that the results are as satisfactory. ‘The actual pressure in atmospheres can be easily found by 22.4 multiplying A by Lag (= 12-108). EFFECT OF FRESH WATER After the first sample of blood was taken, the animal was placed in a tank of sea-water, into which fresh water was then run, so that in a few minutes the water in the tank was fresh. The results of this experiment were obtained from a series of ten fishes, six males and four females, ranging from 61 to 82 centimeters in length, and are shown in Table VII. TABLE VII.—Changes in the freezing point of the blood of Mustelus canis after immersion in fresh water until nearly dead . ‘ Immersion : Weight in . : Change in A time in A of blood ot bloed minutes pd ed bed peed ped 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. ie 0. 0. 0. 0. 0.2: 0. 0. 0. 0. 0. 0. @. 0. 0. SS ee es oo Oubo — 14 ANNALS NEW YORK ACADEMY OF SCIENCES TaBLE VII.—Changes in the freezing point—( Continued.) F ~ : Immersion anieotin Sex sng i bile g okie A of blood ne Flood Q 80 1687 0 1.890 0.000 35 1hO 0.13 5d 1.605 0.285 70 1.53 0.36 85 1.39 0.50 Si 7K 1502 0 1.900 0.000 20 1.84 0.06 40 1.74 0.16 59 1.59 0.31 ‘of 79 1460 0 1.850 0.000 15 ASSL 0.04 30 1.76 0.09 45 1.635 0.215 65 1.50 0.35 75 1.40 0.45 Q 76 1304 0 1.920 0.000 15 1.87 0.05 40 1.74 0.18 313) 1063 0.29 70 147 0.45 80 1.44 0.48 In averaging the results, we may divide the time into five periods of twenty minutes each, the first twenty minutes of immersion constituting the first period and so on. The average change during each period of immersion is as follows: Ist twenty minutes = +0.050° i 2nd twenty minutes = +0.133 3rd twenty minutes = +0.265 4th twenty minutes = +0.400 5th twenty minutes = -+0.470 The average of the ten maximum determinations is +-0.408°. As was found in the series of experiments described on page 9 there are indications here also of individual variations in the reaction of the fishes to the changed environment. Figure 1 is a curve which represents the course of the change in the depression of the freezing point and there- fore a fall in the osmotic pressure of the blood from the beginning to the end of the experiment. This curve is derived from the values computed for each of the twenty minute periods. Certain features of this curve may be here pointed out. There is a slow change at the beginning of the experiment. This continues during the first two of the five periods of immersion. There is then a change in the slope of the curve, indicating SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 15 more rapid changes in the osmotic pressure of the blood. Toward the end of the time, less rapid changes are again indicated. The ordinate which determines the last part of the curve is the average of but two determinations, because most of the animals died before the immersion of a hundred minutes. The ordinate at D more correctly represents the aver- age condition at death. That part of the curve from N to D represents graphically the course of the change in the freezing point of the blood from the normal condition until near death in fresh water. It may be thought that the initial slowness of the changes in the osmotic pressure of the blood is due to the fact that the water is changing from salt to fresh during this period. The slowness, however, continues longer than the time required for the change from salt to fresh +0.40 water. The period of ac- celeration may be due to the gradual failure of the +0.20° defences of the organ- ism. It is possible that the first part of the curve Os Wy 7 oy ~~ a represents changes due = 3 c D E mrsly fo the entrance of |" 1;_Thene tn 8 of tard of Meta det water into the blood of the animal. From this point of view, the second part of the curve might indicate the passage of dissolved substances such as salts out from the blood through the limiting membranes of the body into the water out- side while the outside water continued to pass into the blood. This would mean, of course, profound changes in the physico-chemical constitution of the organism. Dakin (’08) found that the maximum change in the freezing point of the blood of three specimens of Acanthias vulgaris after immersion in fresh water until near death was 0.465°. Garrey found the maximum change in the freezing point of the blood of one Mustelus to be 0.37°. My observations range from 0.27° to 0.50°. That the mag- nitude of the change is not due to the amount of blood taken is shown from the records of specimens 1 and 2. The maximum change in case of No. 1 is .33°, while that of No. 2 was .43°, though six samples of blood were taken from the first specimen, while but four samples were taken from the second specimen. Other cases of the kind can be found. EFFECT OF A CONCENTRATED SOLUTION OF SEA-WATER The change in the osmotic pressure of the blood from the normal con- dition until death in a concentrated solution of sea-water was next ob- 16 ANNALS NEW YORK ACADEMY OF SCIENCES tained. The procedure was in the main as before. The tank in which the specimens were placed after the operation contained about twenty- four liters of sea-water. ‘To increase the amount of salts in solution in this sea-water, about 500 grams of sea-salt were dissolved in a jar con- taining eight liters of sea-water. This was placed above the tank. After the normal sample of blood was obtained, the specimen in each case was placed in the tank of sea-water and the concentrated solution from the jar was at once run into the tank at one end, the overflow running out at the other end. At the same time, the various samples of blood were ob- tained for the determinations of the freezing point, the specific gravity of the water in the tank was taken. On the whole, the specific gravity of the solution was 1.034+. Its A was about 2.60°. The A of the sea- water was about 1.82° and its specific gravity, 1.025. An analysis of the chlorides in both sea-water and in water of the concentration attained at the end of each of these experiments showed that the latter contained about 33 per cent more salts than sea-water. ‘The water in the tank reached this concentration in about fifteen minutes after each experiment began. The results are given in Table VIII. Data with regard to eleven specimens are shown, seven females and three males, ranging in length from 67 cm. to 84 cm. The sex of one animal was not recorded. TABLE VIII.—Changes in the freezing point of the blood of Mustelus canis after invmersion in a concentrated solution of sea-water until near death Immersion n ° ; Sex Le ha in gee time in A of blood ey ae A g 80 1531 0 1.84° 0.000° rz 1.30 0.06 30 1.96 0.12 48 1.99 0.15 65 2.06 0.22 (0 2.08 0.24 2 80 1361 0 1.84 0.000 20 1.93 0.09 30 2-01 0.17 50 2.05 0.21 65 2.11 0.27 80 2.15 0.31 rot 75 1247 0 1.88 0.000 25 pRSE 0.06 40 2.00 0.12 50 2.07 O19 75 2.10 0.22 g 67 950 0 1.80 0.000 15 1.87 0.07 30 1,94 0.14 50 2.00 0.20 > on bo S ioe) i=) bo (ee) SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 13 TaBLE VIII.—Changes in the freezing point—( Continued. ) F . Immersion Miekent tn time in A of blood 8 $ minutes Change in A of blood 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. Dividing the above time into four periods of twenty minutes each and averaging the change in the freezing point of all the specimens for each period, we have the following values: 1st twenty minutes = 0.074° 2nd twenty minutes = 0.125 3rd twenty minutes = 0.190 4th twenty minutes = 0.260 The average of the eleven. maximal changes is 0.24°. Figure 2 is a curve which represents the course of the change in the blood from the 18 ANNALS NEW YORK ACADEMY OF SCIENCES normal condition until near the death of the animal in the above concen- trated solution. Since the curve shows a progressive lowering of the freezing point of the blood, it should be interpreted as showing an in- crease 1n the osmotic pressure of the blood. There is a slight falling off in the effect after an initial sudden change in the freezing point. Toward the end of the time of immersion the change is more rapid again. There is good evidence for believing that the dog-fishes in their migra- tions up and down the coast wander into brackish waters. The organism must be adapted therefore to withstand a moderate amount of decrease in the density of the external medium. Under natural conditions, however, the organism is never subjected to such a concentrated solution as was used in the present experiment. The concentrated salt solution may act = , = m p 2S a chemical stimulus upon 0° 20 40 60’ go the arterioles of the gills, caus- ing them to dilate, and thus bringing about a greater influx -0.20° of blood to the gills, from the capillaries of which the blood would lose water rapidly by 1.40 osmosis. After the initial Fic. 2.—Change in A of blood of Mustelus due stimulus, the arterioles would to immersion of fish in a hypertonic solution : of sed REP Santi denen: recover their tone, there would | be a decreased amount of blood sent to the gills and the loss of water would be retarded. The more rapid increase in A toward the end of the period is evidently an index of greater changes in the physico-chemical constitution of the organism. The above results as to the effect of fresh water and concentrated sea- water on the osmotic pressure of the blood show that, at the time of death in fresh water, there is an average rise in the freezing point of the blood of 0.41° and, at death in the above concentrated solution, a fall of 0.24°, t. é., in the osmotic pressure a reduction of 21.9 per cent and an increase of 12.8 per cent respectively. The values probably represent the lethal limits of departure from the normal constitution of the blood within which protoplasmic activities of this form take place. I must differ from Fredericq and others who would classify the elasmobranchs with the ma- rine invertebrates as to the osmotic relations of their body fluids to the external medium. This conception would imply that the degree of change in the osmotic pressure of the blood is equal to the degree of change in the osmotic pressure of the external medium. In the case of Mustelus, we have seen that this is not true. It may be, however, that some relationship exists between the osmotic pressure of the blood of the SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 19 elasmobranchs and modifications in the molecular concentration of the sea-water. Fresh water has a A of about 0.025°. This is about 1.795° less than that of sea-water. The concentrated solution had an average specific gravity of about 1.034+. The A of such a solution was about _ 2.60°, which is 0.78° greater than that of sea-water. Since the fresh water produced an average rise in the freezing point of the blood of 0.41°, what would be the amount of change in the freezing point of the blood in the concentrated solution if the change in the blood depends upon the change in the molecular concentration of the external medium? We can formulate the following proportion: 1.795°:0.41° ::0.78°: X, where X should equal the change in the blood due to the concentrated solution should the above relation hold true. X equals 0.177° or approximately 0.18°; but the observed maximum change in the concentrated solution was 0.24°. There is a difference between the two values of 0.06°. This would indicate that the relation is only roughly if at all proportional. If the changes took place to a different degree or in a different manner in the two solutions, of course any close relationship would be modified. Furthermore, do these results show any relation between the degree of change in the freezing point of the blood and the time of immersion? In the fresh water experiment, eight records were taken between 40 and 45 minutes from the beginning. The average time was about 42 minutes. The average time of immersion of all ten fishes was 74 minutes. The average final change in the A of the blood was 0.41°. Therefore in the following proportion,—74 min. :42 min. ::0.41° :X, X should have approximately the same value as the A actually observed at the end of the 42 minute period. X equals 0.23°, the theoretical degree of change in A. The observed change in the A of the blood of the eight specimens after 40 to 45 minutes’ immersion in fresh water was 0.18+-°, showing that the observed change lacked 0.04+-° of being as great as the calcu- lated change. ~The average time of immersion in the concentrated solution was 69 minutes. Six determinations were made at about 42 minutes from the beginning of the experiment. If the time relation holds in this case, then X in the following proportion should be similar to the observed change in A at the end of the 42-minute period: 69 min. : 42 min. :: 0.24°:X. But X equals 0.146°. The observed change in 42 minutes was 0.16°. One might conclude from the above considerations that we were dealing here with purely physico-chemical phenomena. It would be haz- ardous, however, to make any sweeping assertions. If we compare the changes in any individual with the average changes in the group, the simple relationships just suggested do not hold. The factors involved 20 ANNALS NEW YORK ACADEMY OF SCIENCES are so many and to such a degree unknown, that although, in the final analysis, the plenomena must be physical and chemical, we are not justi- fied in mainiaining that the relations are definitely quantitative. Figure 3 represents in a graphic manner the relation of the osmotic pressure of the blood to the concentration of the external medium as based upon the conception of a proportional relation existing between the iwo. The abscissas represent freezing point determinations. The ordi- nates represent specific gravities of different solutions of sea-water. Pure A= 0° -0.50° —1.00° —1.50° -2.00° —2.50° -3.00° 17=4D+Y48 1.010 I=%D-¥%S IV=Y4D+3S8 1.020 V=Sea Water Vi= 1.030 ViJ= = 1.035 Fic. 3.—Relation of the A of blood to A of different solutions of sea-water. Curve A-B = A’s of solutions. Curve C—D = A’s of blood water has a A of 0.00° and a specific gravity of 1.000. The curve A—B represents the freezing point of different dilutions of sea-water. This curve is constructed from freezing point data obtained from seven differ- ent dilutions of sea-water. These were as follows: I, pure water; II, three- fourths pure water plus one-fourth sea-water; III, one-half pure water plus one-half sea-water; IV, one-fourth pure water plus three-fourths sea-water; V, sea-water; VI, concentrated sea-water having a specific gravity of 1.030; VII, concentrated sea-water having a specific gravity of SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 91 1.034+. The curve C—D represents the freezing point of the blood at the different concentrations represented by the curve A—B. It is con- structed by drawing a line through the following points: C —the A of the blood at the death of the organism in fresh water; N, the A of normal blood; D, the A of the blood at the death of the animal in the concen- trated solution, having a specific gravity of 1.034-++ and a A of 2.60°, the effect of which has been described in this section of the paper; E, the A of blood of Squalus acanthias in harbor water which has a A of about #00°. A further account of this is given later (on page 31). That the oper- ation of destroying the cord did not modify the results is strongly indi- cated by the following instance: A large Mustelus canis was operated on in an attempt to collect a sample of its urine. ‘The spinal cord was destroyed in the manner already indicated. The ab- \| dominal cavity was opened, the rectum | was ligated and a large glass tube was fas- tened in the cloaca. The animal was then placed on a support in the sea-water in such a way that the head as far back as the last gill slit was under water. The abdominal incision was closed and the surface of the body was kept moist with a cloth wet with sea-water. At the end of Fic. 4.— Respiratory movements twenty-four hours the fish was still alive Sg ee et oe > struction of spinal cord. and breathing normally. When the peri- cardium was opened, the heart was seen to be beating regularly. Figure 4 is a record of the respiration at the end of twenty-four hours, the time record indicating intervals of two seconds. Although the experiment was a failure as far as its primary purpose was concerned, it proved that the above operation in itself is no cause of immediate death. Sheldon (709) has found that Mustelus may live for a week after a similar de- struction of the cord. Parker (710) has called attention to “the ease with which this fish resists the adverse effects of operations.” In a series of earlier experiments, the results of which are given in Table VI, on the effect of immersion in fresh water on the freezing point of the blood, I first defibrinated the blood, then centrifuged it, and used the serum for the determination of the freezing point. About 10 to 15. ¢. of serum was used for each determination. In these preliminary experiments, blood was drawn from each specimen but once. In the case of the specimens immersed in fresh water, the 95 ANNALS NEW YORK ACADEMY OF SCIENCES oe ow blood was drawn after they had been immersed for about an hour. The results were as follows: TABLE VI.—Showing the depression of the freezing point of the serum of Mustelus in salt water and after immersion in fresh water for one hour Serum from fishes immersed Serum from normal! fishes pnitiroah Gr atemanciane No. specimen A No. specimen A 1 1 920° ] 1.580° 1 1.950 4 1.460 2 1.805 2 1.595 2 1.950 2 1.595 1 1.947 2 1.540 Average, 1.914° Average, 1.554° The average rise in the freezing point of the serum of these dog-fish after immersion in fresh water for an hour is thus seen to be +0.36°. CHANGES IN THE OSMOTIC PRESSURE OF THE BLOOD BROUGHT ABOUT BY A RETURN TO SEA-WATER AFTER IMMERSION IN FRESH WATER OR CONCEN- TRATED SEA-WATER The above experiments on the effects of diluted and concentrated solu- tions of sea-water indicate that to cause a decrease in osmotic pressure with the diluted solutions there must be currents outward through the limiting membranes of the body; to cause an increase with concentrated solutions there must be currents inward. Is it possible to demonstrate these two effects in the same individual? If reversibility is possible, then after a fall in osmotic pressure resulting from immersion in a diluted solution of sea-water, the original pressure should apparently be gained when the animal is returned to normal sea-water. The experiments re-_ ported in Table IX were carried out to test this possibility. TABLE IX.—Effect on the blood of transference of Mustelus from sea-water to fresh water followed by subsequent return to sea-water Sea-water Fresh water Sea-water Normal A | Duration of f Change | Duration of of Change Amount of blood immersion oL va from immersion = d from of in degrees | in minutes ie normal in minutes ee normal reversal 1=1.835 35 1.620° | +0.215° 25 1.685° |+0.15 °| 0.065° 2=1.895 5d 1.655 | +0.240 50 1.785 +0.115 | 0.125 3=1.875 30 1.675 |-+0.200 50 1.760 |+0.115 | 0.085 4=1.905 25 1.665 | +0.240 100 1.785 +0.120 | 0.120 SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 93 It is clear that, after immersion in fresh water, we get as before a rise in the freezing point of the blood. After the return to sea-water, the A is lowered and the osmotic pressure is increased again; but the normal os- motic pressure of the blood is not regained, even though the return to sea-water is as long or even longer than the sojourn in fresh water. This is shown in the case of the fourth specimen; for after 25 minutes in fresh water the freezing point had been raised 0.24° above normal, but when the fish had been returned to sea-water for 100 minutes the freez- ing point was still 0.12° above normal. Figure 5 shows the changes in the A of the blood of this specimen. The fish was in fresh water from F to F* and in sea-water from Ft to 8. The base line represents the normal A; the abscissas, time in minutes, and the ordinates, the rise in the freezing point of the blood. At first one might conclude from these experiments that the limiting membranes were not as permeable in one direction as the other. A second experiment of this nature will be de- F 20’ 40’ 60’ 80’ 100’ 120’ 140’ Fic. 5.—Changes in A of blood of Mustelus due to immersion in fresh water followed by return to sea-water scribed. In this case, the mixed blood of the two specimens was used for the determination of the normal A, 1.895°. After 75 minutes’ immersion in fresh water, there was noted a rise in the freezing point of the mixed blood of 0.245°. Both specimens were then returned to sea-water and one died soon after. A determination was made from the blood of the other 225 minutes after the return, and its A was 0.05° above the normal A. Although there was an apparent return to the normal condition, the animal was injured in some way, for it died soon after. In fact, it is not quite correct to assume that the normal condition of the blood was re- gained for the last figure given, 7. e., 0.05° is obtained by subtracting the final A of the blood of this fish from the A of the mixed blood of this fish and the other which died earlier. The number of molecules and ions in solution in the blood had decreased after immersion in fresh water. Cer- tain parts normally present had escaped into the surrounding medium. The return of the organism to its normal medium did not suffice for the return to the blood plasma of the normal quantitative relation of parts in solution. Concentrated solutions were also tried. Two such experiments will be 24 ANNALS NEW YORK ACADEMY OF SCIENCES described. In the first, three dog-fishes were used. The A of the com- bined blood of the three was 1.92°. They were then placed in a concen- trated solution of sea-water having a A of about 2.60° for forty minutes, at the end of which time the A of the mixed blood from the three was %.11°, the freezing point having fallen 0.19°. Then the specimens were returned to sea-water for eighty minutes, when A was 2.04°, showing that although the freezing point had risen 0.07°, it still lacked 0.12° of being normal. In the second experiment, three dog-fishes were also used. The normal A of their mixed blood was 1.87°. They were placed for sixty minutes in a tank containing a concentrated solution of sea-water having a A of about 2.15°. At the end of this time the A of their mixed blood was 2.00°, showing a fall in the freezing point of 0.13°. The three speci- mens were then returned to a concentrated solution having a A of 2.60° for sixty minutes more, at the end of which time the A of their combined blood was 2.18°, showing a total fall in the freezing point of the blood of 0.31°. Sea-water was then run into the tank for two and one-half hours, when the value of the A of the blood was 1.98° ; that is in the two hours and a half after the return to sea-water the freezing point of the blood rose 0.20°, but was still 0.11° short of its value at the beginning of the experiment. Thus with neither a hypotonic nor a hypertonic medium did the organisms regain the normal A after the return to sea-water, even though they were kept in the sea-water as long or even longer than in the diluted or concentrated solution. One other experiment of this nature will be referred to briefly. A somewhat small stream of concentrated sea-water was passed into the mouth and out through the gills of a large female dog-fish for 45 min- utes. The A of its blood fell 0.09°. The small size of the stream possibly explains the small change in A. A stream of fresh water was then turned on gradually and A was again taken 60 minutes later. A proved to be 0.16° above its value in the concentrated solution and was even higher by 0.07° than the normal. The fsh was then returned to sea-water for 60 minutes when A was 0.03° lower than the normal. In this case we have evidence of an increase in the osmotic pressure of the blood due to a concentrated external medium. A fall in the osmotic pressure results when the organism is subjected to a dilute external medium, after which it rises to the normal condition when the animal is returned to sea-water. It should be noted that, in changing the concentrated solution to fresh water, the concentrated solution was gradually replaced by fresh water and this in turn by the sea-water again. The fish was unusually large, being 120 em. in length. It rested with its dorsal surface upon a support out of the water and the stream entered its mouth through a rubber tube SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 25 having an inside diameter of about a centimeter. It seems to me that the normal A was regained in this case, because the external media produced but a small degree of departure from it. It is interesting to note that the maximum change produced in A is about equal to the normal range in A of normal dog-fish blood as described in the first section of this paper. The results with the other fishes indicate, however, that osmotic phe- nomena are complicated by the presence of other factors. ROLE OF THE GILLS IN THE MODIFICATIONS Considerable difference of opinion exists as to the part of the body that is concerned in the osmotic changes in the blood brought about by changes in the osmotic pressure of the surrounding medium. As stated above, there are three structures that may be the seat of this phenomenon, namely, the skin of the body, the lining of the alimentary tract and the gill membranes. Any one or all of these structures may be conceived to share in the above processes. The surface of the body of the dog-fish is covered with a closely associated system of dermal plates forming, with other structures of the skin, a tough coat through which it would appear that fluids could pass with the greatest difficulty if at all. The cells of the intestinal tract are known to exert a selective action on materials present in the intestine, and therefore we should expect that solutions more or less concentrated than sea-water which would possibly accom- pany the swallowed food would be passed out through the cloaca before osmotic changes of any account would take place. Furthermore, my ob- — servations indicate that the cesophagus and the cloacal aperture are kept closed during the greater part of the time, and are probably opened only during the taking in of food and the getting rid of waste. Therefore the wall of the gut would not ordinarily be exposed to solutions differing in density from that of sea-water, even though the whole fish were entirely immersed in such solutions. The gills, however, are always freely exposed to the external medium. Each gill filament contains a fine capillary loop composed of an afferent vessel and an efferent vessel supported by connective tissue. Covering the capillary apparatus is an extremely thin epithelial membrane, so that there are but two thin layers of cells between the water and the blood stream, namely, the gill membrane and the endothelial wall of the capil- lary. If the rich capillary supply of the gills be taken into account, there is in effect a large, broad sheet of circulating blood separated from the water by an extremely thin membrane known to be permeable to gases. A priori, therefore, it would seem that the osmotic changes in the blood described above might take place through the gills. 96 ANNALS NEW YORK ACADEMY OF SCIENCES The following views have been maintained with regard to this: Bert (71) gave a minute description of the death of a fresh water fish in salt water. He described the gills as changing from bright red to dark red in color, and said that the congested condition of these membranes per- mitted the blood to transude through them. He found the corpuscles to be crenated, shriveled and piled up in masses in the capillaries. A tench suspended in a vessel of sea-water lived a long time if the head was kept out of the sea-water and the gills were bathed with fresh water. Fred- ericq (704) stated, “I can in a short time change the proportion of salts in the blood of Carcinas menas, even to doubling the quantity, if I bring the animal into water more salty than sea-water. This is due to a pe- culiarly modified epithelium of the gill membranes by which substances dissolved in the water can go through the gills easily.” With regard to the fishes Fredericq said, “Les vertébres aquatiques des poissons se com- portent tout differement. Chez eux, la branchie, si permeable aux echanges gazeux de la respiration, semple au contraire constituer une barrier presque infranchissable aux sels dissous dans l’eau de mer. La sang des poissons de mer n’est guére plus sale, au gout, que le sang des poissons (eau douce.” Quinton (’00), however, held the view that salts as well as water can pass through the external surface membranes of ma- rine animals. In a later investigation by Bottazzi and Enrique (701), it was shown that the stomach wall of the mollusk, Aplysia, is normally impermeable to salts. They concluded that the stomach wall is a semi- permeable membrane, allowing the water to pass through but excluding the salts, and proposed the hypothesis that osmotic equilibrium is main- tained by the liver, functioning as an organ of resorption. Siedlechi (703) found that the stickleback, Gasterosteus, resisted the effects of sud- den transitions from salt to fresh water and vice versa. This author held that the structure of the skin amply protects the organism from the effects of changes in the external medium. Schucking (’02) showed that salts left the body of Aplysia, though the mouth and anus were ligated. This result, together with those obtained by Quinton and Bottazzi, shows that the surface membranes of Aplysia are permeable. Overton (04) con- cluded that the skin of amphibians is permeable to water and but shghtly permeable to salts. Greene (705) from his studies of the Chinook salmon inferred that in that species all three structures are impermeable. He accounted for the fall in the osmotic pressure of the blood at the spawn- ing grounds as being due to absence of food and the poor physical condi- tion of the fishes. Garrey (705) tied off both ends of the alimentary canal of Nereis and Chetopterus and found that, if placed in fresh water, the animals swelled and increased in weight, which showed the permea- SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS at bility of the body wall to water. Garrey suspended Limulus so that the gills alone were immersed in a solution of one-half sea-water plus one-half fresh water. A decrease in the osmotic pressure of the blood took place which demonstrated the permeability of the gills. Sumner (’06) inferred that the structure of the skin of most teleosts was an effective barrier to osmotic exchanges between the tissues of the fish and the external medium. He devised an apparatus by which the body was immersed in a solution of one concentration, while the gills were bathed by water of another concentration. In an experiment with the carp, Cyprinus carpio, the body of the fish was immersed in fresh water and sea-water bathed the gills. There was a loss of weight at the end of the experiment. In the second place, the body of this fresh water fish was immersed in sea-water and fresh water was supplied to the gills. The fishes not only continued to live longer than in the first instance, but there was no loss in weight. The result showed that no osmotic changes took place through the body membranes of the carp. When the body of the tautog, Tautoga onitis, a marine form, was immersed in sea-water and the gills were bathed with fresh water, the fishes died in from two to three hours. On the other hand, when the gills were supplied with sea- water and the body was immersed in fresh water, the fishes were appar- ently not affected. These ingenious experiments of Sumner, in which it will be noted that the fishes were not injured, contribute strong evidence for the conclusion that the gills alone are concerned in osmotic changes. Dakin (’08) called attention to the fact, as did Greene, in the case of the salmon, that while the contents of the stomach of the lump sucker are osmotically the same as sea-water, the osmotic pressure of the coelomic fluid, though separated from the cavity of the intestine by a very thin wall, is the same as the osmotic pressure of the blood, which is much less than that of sea-water. He thus proved that the wall of the gut is nor- mally impermeable to salts except in the processes of nutrition and was inclined to the belief that the membranes are semi-permeable. From different points of view, the evidence indicates that the gills con- stitute the pathway by which the osmotic changes take place. Sumner alone has attacked the problem directly. Dakin criticised Sumner for not excluding the gut as a possible factor. I concluded to investigate this problem in the case of the dog-fish. The following facts justify Sumner’s conclusion : The average A of the blood of two dog-fishes immersed in fresh water for sixty minutes was found to be 1.597°. A male Mustelus canis, sev- enty-eight centimeters long, was pithed, the body cavity was opened, the cesophagus was ligated, and the fish was placed on a support out of the 28 ANNALS NEW YORK ACADEMY OF SCIENCES water. A stream of fresh water was then made to flow into its mouth and out through its gills. At the end of fifty minutes the freezing point of the blood of this specimen, whose gills alone were exposed to the fresh water, was 1.585°. As great a change had taken place in the osmotic pressure of its blood as had taken place in the case of those whose gills, intestinal wall and body surface were all exposed to the fresh water. The operation on the five following specimens was similar to that on the preceding specimen. 1.90 —0.04 Ge2uie 1.90 —0.04 §n50.5 °° 1.90 —0.04 Z Q 84 1474 9.55 A.M 1.81 0.000 67 10. 2-5 ** 1.83 —0.02 ) 0 Sa 1.83 —0.02 Lie 1.86 —0.05 12.00 M 1.85 —0.04 3.00 P.M 1.86 —0.05 8 Q 112 4366 9.35 A.M isk 0.000 18 TORLO 1.84 —0.03 E200, 5 °f 1.85 —0.04 1.30 P.M 1.86 —0.05 FOO" 1.86 —0.05 9 2) 124 649z 3.00 P. M 1.84 0.000 28 5 at: aan 1.89 —0.05 4.00 ‘ 1.90 —0.06 2 Us | aaa 1.92 —().08 5-00: ** 1.92 —0.08 Oral i 1.93 —0.09 FOO, he 1.92 —0.08 [ew ey 1.92 —0.08 Secs 1.92 —0.08 8-50. 9)" 1.93 —0.09 36 ANNALS NEW YORK ACADEMY OF SCIENCES prove fatal. Hyde (’08) estimated that the blood of the skate is equal to one-twentieth of its body weight. Even if we assume that the total quantity of blood of Mustelus is equal to five per cent of its body weight, in none of the preceding experiments was one-half of the total blood of the body taken. ‘Table XIV shows the results of the experiments in which the A’s of the blood were obtained from different samples taken at intervals from the caudal artery of fishes immersed in sea-water. In the above series of experiments, more blood was intentionally taken for each determination of A than was used in the preceding cases. As indicated above, the object of the experiments was to ascertain the effect of bleeding on the osmotic pressure of the blood. There was no difficulty in obtaining blood from any of the fishes experimented upon in the pres- ent connection. All were alive and breathing regularly at the time the last sample was obtained. The percentage of the total quantity of the blood given in each case is only.a rough estimate based on the assumption that the total quantity equals five per cent of the body weight. In esti- mating this, the last sample was not included. In reviewing the results, it is to be noted that there is a slight rise in the freezing point of the blood of specimens 1, 2 and 5. The remaining six show a fall in the freezing point. On referring to the accompanying data in each case, it is found that the rise or fall in A is not related to the sex, length or weight of the fishes, or to the amount of blood taken. In many of the cases after the initial change, there is no further modification in A. It is possible that these small variations from the normal A are indications of the nor- mal fluctuations in the osmotic pressure as maintained on page 6. The evidence presented in Table XIV is offered as further support for this conclusion. Finally, attention is called to the fact that the maximum changes are slight as compared with those recorded as due to the effects of fresh water and concentrated sea-water. On the whole we are justi- fied in concluding that the effects recorded in Tables VII and VIII were due to the modifications in the molecular concentration of the ex- ternal medium. Buglia (708) found that simple bleeding produced in the physico-chemical properties of dog’s blood variations absolutely negligible as compared with those obtained after injections of salt solutions hyper- tonic to the blood. ADDITIONAL CHANGES IN THE BLooD DUE TO ALTERATIONS IN THE CONCENTRATION OF THE EXTERNAL MEDIUM CHANGES IN THE ERYTHROCYTES One might conclude from the above changes in the osmotic pressure of the blood of fishes exposed to fresh water that the corpuscles were laked SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 34 by the dilution due to the entrance of water into the blood and that this might be a contributing cause of death. In fact, Mosso (790) working at Naples made this the basis of his explanation of the death of elasmo- branchs under this condition. The freezing point of the sea-water from the Mediterranean is about 26 per cent lower than that of the water at Woods Hole. The degree of change to which the fishes were subjected when placed in fresh water was therefore greater in the case of the fishes with which Mosso worked. This difference may account in part for the divergence of my results from those of Mosso. Mosso stated that, if the tail of Scyllwwm was cut off after the fish had been in fresh water for half an hour, no more blood flowed from the artery, while the heart still con- tinued to beat. On the other hand, I found that blood might be obtained from the caudal artery of Mustelus up to the point of death in fresh water, 7. e., from one to two hours. Mosso also claimed that the serum remained almost normal at the time of death in fresh water. We have here noted a profound lowering of the osmotic pressure of the serum. The results obtained by Garrey (705), Dakin (708) and myself show that this statement of Mosso’s cannot be correct. Mosso believed the real cause of death to be due to suffocation. By the action of the fresh water, the red blood cells go to pieces and clog up the capillaries of the gills, thereby cutting off the exchange of gases in these structures. Following up this hypothesis, Mosso studied the osmotic resistance which the red cells offered to different salt solutions. For example, the erythrocytes of selachian blood were destroyed in 2.5 per cent solutions of sodium chloride and the fluid soon became red. Teleosts like Conger and Murena had a greater resistance and first lost their hemoglobin in a 0.3 per cent NaCl solution. Mosso found that fresh water forms possessed blood more resistant to salt solutions of different dilution than marine teleosts, while anadromous fishes like Angutlla and Acipenser possess blood cells which are especially resistant to dilute salt solutions. On account of the divergence between my observations and those of Mosso, I concluded to ascertain whether at the time of death as the result of immersion of Mustelus in fresh water its corpuscles were laked. This was ascertained in the following way: The spinal cord of a dog-fish taken from sea-water was destroyed. About ten cubic centimeters of blood were drawn from the caudal artery. This was closed, and the fish was trans- ferred to sea-water which was rapidly changed to fresh. Near the time of death, the artery was opened a second time and a second sample of blood was obtained. Soon after each sample of blood was taken, it was defibrinated. Then each was placed in a separate centrifuge tube and the two were simultaneously centrifuged. At the end of this process, the 38 ANNALS NEW YORK ACADEMY OF SCIENCES serum of the normal blood was perfectly clear, while that of the other showed in some cases faint traces of laking. In other cases it was difficult to detect any such indication. On the whole, it was thus demonstrated that there was no marked laking of the corpuscles after immersion of the fish in fresh water. In Fig. 7, N represents the osmotic pressure of the blood of Mustelus, in sea-water; F represents the osmotic pressure of the blood at the time of death in fresh water; while S represents the osmotic pressure of the first solution of NaCl in which the blood is laked. In solutions more concentrated than this the blood is not laked. I made camera lucida drawings of the corpuscles from both fishes and observed no measurable differences in size. These corpuscles are oval and Nok 36 Nos se Fic. 7.— Diagram showing comparative Fic. 8.—Showing the difference between A’s of blood of Mustelus in sea-water, the ratios of volume of corpuscles to N; in fresh water, F; and of saline so- plasma in normal blood, N, as compared lution, S, in which blood is first laked. with blood taken from fishes after im- mersion in fresh water, H. flat, so that, in preparations made of them, the flat surface only would be observed and there would appear no indication of their thickness. It then occurred to me to make hematocrit studies of the blood under normal and experimental conditions. The following results were obtained. The ratio of the volume of corpuscles to that of serum of normal blood was found to be about 23 to 77, 7. e., the corpuscles form less than 25 per cent of the total volume of defibrinated blood. Blood from the same specimen near death after immersion in fresh water showed a ratio of 31 to 69, that is, the corpuscles occupied 31 per cent of the total volume of the defibrinated blood. In determinations made defibrinated blood in a graduated centri- fuge tube, I found that in normal blood the ratio of corpuscle to serum SCOTT, STUDY OF CHANGES IN MUSTELUS CANIS 39 was as 20.5 to 79.5. After immersion in fresh water the ratio was 30.77 to 69.23. Fig. 8 shows this difference. In this figure, N represents the _ ratio between the volume of corpuscles and serum in normal blood. H represents the ratio from blood taken from fishes after immersion in fresh water. Shaded portions represent corpuscles. Considering these results in connection with those obtained by the use of the camera lucida, we may conclude that at least some of the corpuscles are swollen after immersion of the fish in fresh water. The faint trace of laking at the end of the experiment indicates that at least some of these swollen cor- puscles cannot withstand the increased pressure of distension by the ab- sorption of water. These burst and cause the faint trace of laking noted above. In fact, in preparations made of the corpuscles of a fish that had died in fresh water, some corpuscles were found broken down. Since Mosso claimed that the resistance of the erythrocytes of fishes varied in a general way with the salt content of the blood, I determined to ascertain the strength of solutions of NaCl which would cause the laking of the blood of elasmobranchs common at Woods Hole. He found that the erythrocytes of selachians at Naples were laked by solutions more dilute than 2.5 per cent NaCl. The sea-water from the Mediterranean is. isotonic with a 3.8 per cent sodium chloride solution. oe fos a —- = ed age we > . es * , t + 7 als oe, ~. x r Tr ¢ ° ». - wid. ~ . , , *. + SS 4 ie aa os ; 3 - 7 Se -~ _ ANNALS OF THE NEW YORK ACADEMY OF SCIENCES eo _ Vol. XXIII, pp. 77-83 Editor, Epmunp Ot1s Hovey E CORRECTIONS AND ADDITIONS TO “LIST OF TYPE SPECIES OF THE GENERA AND. _ SUBGENERA ‘OF FORMICIDE” =~ BY Wittram Morton’ WHEELER _ ss | ie EW “BORK: ~~ >>. PUBLISHED. BY THE ACADEMY ES ae 29 May, 1913 : THE NEW YORK ACADEMY OF SCIENCES (Lyceum or Narurau History, 1817-1876) OFFICERS, 1913 President—EMeErson McMituin, 40 Wall Street Vice-Presidents—J. EpMunp Woopmayn, W. D. MarrHew CHarLes Lane Poor, WenpDELL T. Bus Corresponding Secretary—HeEnry E. Crampron, American Museum Recording Secretary—Epmunp Oris. Hovey, American Museum T'reasurer—HENryY L. DoHerty, 60 Wall Street Librarian—Ratpu W. Tower, American Museum Editor—EpMunp Otis Hovey, American Museum SECTION OF GEOLOGY AND MINERALOGY ‘ Chairman—J. BE. Woopman, N. Y. University Secretary—Cuar.es T. Kirx, Normal College SECTION OF BIOLOGY Chairman—W. D. Marruew, American Museum | P Secretary—Wi.u1amM K. Grecory, American Museum 3 SECTION OF ASTRONOMY, PHYSICS AND CHEMISTRY : Chairman—CHARLES Lane Poor, Columbia University ; 4 Secretary—F. M. PEDERSEN, College of the City of New York SHCTION OF ANTHROPOLOGY AND PSYCHOLOGY a Chairman—Wenvett T. Busu, 1 West 64th Street ey Secretary—Roxsert H. Lowiz, American Museum | Ee | The sessions of the Academy are held on Monday evenings at 8:15 o'clock from October. to May, inclusive, at the American Museum of . Natural History, 77th Street and Central Park, West. 7 [ANNALS N. Y. Acap. Scr., Vol. XXIII, pp. 77-83. 29 May, 1913] CORRECTIONS AND ADDITIONS TO “LIST OF TYPE SPECIES OF THE GENERA AND SUBGENERA OF FORMICIDA” By WILLIAM MortToN WHEELER Since my list of generic and subgeneric types of the Formicide was published,t Mr. Sievert Rohwer has kindly called my attention to some type determinations of earlier dates than those I recorded and especially to the genus Cephalotes Latreille, which has been incorrectly cited by Dalla Torre in his “Catalogus Hymenopterorum” and generally ignored by myrmecologists. Prof. Carlo Emery has called attention to a few omis- sions and incorrect determinations of types,? and I have myself detected several others. While seizing the opportunity to make corrections, I have added the types of a number of new genera and subgenera established during or since the publication of my paper. In this list of additions there are a number of subgenera of Camponotus recently published by Forel. Strangely enough, he does not designate the types, although noth- ing could have been more necessary in splitting up such a huge and per- plexing genus as Camponotus. When he mentions several species belong- ing to one of these new subgenera, I have uniformly selected the first: as the type, not because I am an unqualified adherent to the “first species rule,” but because Forel probably intended to indicate the first species as the type. CORRECTIONS Aneleus Emery.—I cited Solenopsis similis Mayr as the type of this subgenus, supposing it to be monobasic, but this is far from being the case. Emery cites six species of Pheidologeton as belonging to Aneleus, and as he mentions Ph. pygmeus Emery as the first in his list, this should be regarded as the type, especially as the soldier or most characteristic phase of the oldest known species, S. similis, has not been described. Atopogyne Foret.—Emery prefers to regard Formica depressa Ja- treille as the type of this subgenus, instead of Crematogaster hellenica Forel, the species I selected, because depressa is the most characteristic 1 Annals N. Y. Acad. Sci., Vol. XXI, pp. 157-175. 1911. 2Les Espéces-Type des Genres et Sous-Genres de la Famille des Formicides. Ann. Soc. Ent. Belg., LVI, pp. 231-233. 1912. (77) 78 ANNALS NEW YORK ACADEMY OF SCIENCES species and because it was Forel’s intention to regard it as the type, as he subsequently stated in a letter to Emery. Azteca Forrt.—The type of this genus is not Tapinoma instabilis F. Smith, but Azteca instabilis Forel (=A. muellert Emery), as Emery maintains (Genera Insect. Fasc. 137, p. 31, 1912). Cataglyphis Férster.—This should rank as an independent genus and not as a subgenus of Myrmecocystus. Cephalotes Larreitte.—The type is incorrectly cited as Formica cephalotes LL. (==Atta cephalotes) instead of F. atrata L. (= Crypto- cerus atratus). The genus Cephalotes was unfortunately regarded by Dalla Torre as a synonym of Atta Fabr., but it is evidently synonymous with and must replace Cryptocerus, as Mr. Rohwer maintains (im lit- teris). Latreille described Cephalotes in the third volume of his Hist. Nat. Crust. Insect., p. 357, which was published in 1802. The only spe- cies cited as an example is Formica atrata. On this same species he also based his genus Cryptocerus in the thirteenth volume of the same work, published in 1804 according to Mr. Rohwer, or 1805 according to Hagen (Biblioth. Ent., p. 453) and Dalla Torre. It is evident, therefore, that Cryptocerus is isogenotypic with the earlier Cephalotes and must be con- signed to the synonymy. Condylodon Lunp.—The word “monobasic” should be added. Cosmacetes SprnoLta.—The word “monobasic” should be added. Crematogaster Lunp.—Prof. Emery insists that the name of this genus should not be written Cremastogaster, because Lund, who mentions it only once, gives the word with a single s, and it is not certain that we are dealing with a typographical error. Emery also implies that Bing- ham was wrong in designating Formica scutellaris Olivier as the generic type. Lund cites no species in connection with Crematogaster, which is saved from being a nomen nudum only by the clear description of the abdomen, which exhibits peculiarities not found in any other genus of ants. As he had in mind only Brazilian species, Emery believes that one of these, e. g., Formica acuta Fabr., should be selected as the type. It might be contended, on the other hand, that in such a widely distributed and homogeneous genus as Crematogaster, it is better to select the com- mon European form C. scutellaris, which is, moreover, closely related to the typical North American C. lineolata Say. At any rate, it is too late to make a change, because Bingham’s designation, unless an earlier is found, will have to stand. Eciton LATrErLLE.—Shuckard (Swainson and Shuckard, Hist. & Nat. Arrang. Ins., p. 173. 1840) states that Formica hamata Fabr. is the type of this genus. WHEELER, ADDITIONS TO FORMICIDA 79 Formica L.—Formica rufa L. is given as the type of this genus by Girard (Traité Elém. d’Ent., II, p. 1011. 1879). Gnamptogenys Rocrer.—My designation of Hctatomma concinnum F. Smith (nec Mayr) as the type of this subgenus is erroneous. Hmery has rightly selected G. tornata, the first of two species described by Roger. Holcoponera Mayr.—Now ranks as an independent genus. Labidus Jurine.—According to Mr. Rhower, Latreille designated L. latreillei Jurine (= EHciton (Labidus) cecum Latr.) as the type of this subgenus as early as 1810. Leptothorax Mayr.—Emery selects L. clypeatus Mayr as the type of this genus, both because it was the first species described by Mayr and because L. acervorum Nylander has already been made the type of the subgenus Mychothorax by Ruzsky. Myrmecia Fasricius.—Shuckard (Hist. & Nat. Arrang. Ins., p. 173. 1840) designated Formica gulosa Fabr. as the type of this genus. Myrmica LarTreILye.—Girard designated Formica rubra L. as the type of this genus (Traité Elém. d’Ent., II, p. 1016. 1879). Oecodoma LatrEeILLe.—Formica cephalotes L. is designated as the: type of this genus by Shuckard (Hist. & Nat. Arrang. Ins., p. 174. 1840). Rhytidoponera Mayr.—This now ranks as an independent genus. I selected Hctatomma metallicum. F. Smith as its type. Emery designates: | £. araneoides Le Guillou (—rugosum F. Smith) (Gen. Insect., Fase. 118. 1911), because it is the first species cited by Mayr and because he,, Emery, had previously (1879) based the subgenus Chalcoponera on E.. metallicum. I do not regard the first reason as cogent; the second is, of: course, valid and sufficient. Tetramorium Mayr.—formica cespitum L. is designated as the type of this genus by Girard (Traité Elém. d’Ent., II, p. 1016. 1879). Trigonogaster ForeLt.—Through a blunder of my amanuensis or of the printer the type of Triglyphothriz is repeated under this head. The correct type is Trigondgaster recurvispinosa Forel. ADDITIONS Allopheidole Foret. Mém. Soc. Ent. Belg., XIX, p. 237. 1912. (Sub- genus of Pheidole.) Type: Pheidole kingi Ern. André (by present designation). Atopodon Fore... Rey. Suisse Zool., XX, p. 771. 1912. (Subgenus of Acropyga.) Type: Acropyga (Atopodon) ineze Forel. (First of three species by present designation. ) 80 ANNALS NEW YORK ACADEMY OF SCIENCES Atopula Emery. Ann. Soc. Ent. Belg., LVI, p. 104. 1912. (Subgenus of Vollenhovia. ) Type: Atopomyrmex nodifera Emery (designated by Emery). Chalcoponera Emery. Ann. Mus. Stor. Nat. Genova, XXXVIII, p. 547. 1897. (Subgenus of Rhytidoponera.) Type: Ectatomma metalliicum F. Smith (designated by Emery). Decapheidole Forrt. Mém. Soc. Ent. Belg., XIX, p. 237. 1912. (Subgenus of Pheidole.) Type: Pheidole perpusilla Emery (by present designation). Emeryopone Foret. Rev. Suisse Zool., XX, p. 761. 1912. Type: Emeryopone buttel-reepent Forel (monobasic). Forelomyrmex nom. nov. for Janetia Foren (1899), which is preoccu- pied by Janetia Kieffer (1896), a genus of Itoniidee (Cecidomynde@). Holcoponera Cameron. Whymper’s Travels in the Andes, Suppl., p. 92. 1891. (=—Cylindromyrmer Mayr.) Type: Holcoponera whympert Cameron = Cylindromyrmex striatus Mayr (monobasic). Hylomyrma Foret. Mém. Soc. Ent. Belg., XX, p. 16. 1912. (Sub- genus of Pogonomyrmez.) Type: Pogonomyrmex (Hylomyrma) columbicus Forel (designated by Forel). Isopheidole Forret. Rev. Suisse Zool., XX, p. 765. 1912. (Subgenus of Pheidole.) Type: Aphenogaster longipes F. Smith var. longicollis Emery (mono- basic). Leptomyrmula Emery. Genera Insect., Fase. 137, p. 16, nota. 1912. Type: Leptomyrmex maravigne Emery (monobasic). Machaerogenys Emery. Gen. Insect., Fasc. 118, p. 100. 1911. (Sub- genus of Leptogenys.) | Type: Leptogenys truncatirostris Forel (designated by Emery). Mesomyrma Srirz. Stitzb. Gesell. naturf. Freunde Berlin, p. 363. 1911. (Subgenus of Podomyrma.) Type: Podomyrma (Mesomyrma) cataulacoidea Stitz (monobasic). Metapone Foret. Rev. Suisse Zool., XIX, p. 447. 1911. Type: Metapone greeni Forel (monobasic). Myrmamblys Foren. Mém. Soc. Ent. Belg., XX, p. 90. 1912. (Sub- genus of Camponotus.) Type: Camponotus reticulatus Roger (by present designation). Myrmentoma Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus. ) Type: Formica lateralis Olivier (by present designation). WHEELER, ADDITIONS TO FORMICIDA 81 Myrmepomis Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus.) Type: Formica sericeiventris Guérin (by present designation). Myrmeurynota Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus. ) Type: Camponotus eurynotus Forel (by present designation). Myrmobrachys Foret. Mém. Soc. Ent. Belg., XX, p. 91. 1912. (Sub- genus of Camponotus. ) Type: Formica senex F. Smith (by present designation). Myrmogigas Foret. Mém. Soc. Ent. Belg., XX, p. 91. 1912. (= Dinomyrmex Ashmead; subgenus of Camponotus.) Type: Formica gigas Latreille (by present designation). Myrmogonia Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- . genus of Camponotus.) Type: Camponotus laminatus Mayr (by present designation). Myrmophyma Foret. Mém. Soc. Ent. Belg., XX, p. 91, 1912. (Sub- genus of Camponotus.) Type: Camponotus capito Mayr (by present designation). Myrmorhachis Forre,. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus. ) Type: Camponotus polyrhachoides Forel (by present designation). Myrmosaga Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus. ) Type: Camponotus kelleri Forel (by present designation). Myrmosericus Forex. Mém. Soc. Ent. Belg., XX, p. 91. 1912. (Sub- genus of Camponotus.) Type: Formica rufoglauca Jerdon (by present designation). Myrmosphincta Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus.) Type: Formica sexguttata Fabricius (by present designation). Myrmotarsus Foret. Mém. Soc. Ent. Belg., XX, p. 92. 1912. (Sub- genus of Camponotus. ) Type: Formica mistura F. Smith (by present designation). Myrmothrix Foren. Mém. Soc. Ent. Belg., XX, p. 91. 1912. (Sub- genus of Camponotus.) Type: Formica abdominalis Fabricius (by present designation). Myrmotrema Foret. Mém. Soc. Ent. Belg., XX, p. 91. 1912. (Sub- genus of Camponotus.) Type: Camponotus foraminosus Forel (by present designation). 82 ANNALS NEW YORK ACADEMY OF SCIENCES Myrmoturba Foret. Mém. Soc. Ent. Belg., XX, p. 91. 1912. genus of Camponotus. ) Type: Formica maculata Fabricius (by present designation). Neoformica subgen. nov. (Subgenus of Formica.) Type: Formica pallidefulva Latreille (by present designation). Octostruma ForEL. Meém. Soc. Ent. Belg., XIX, p. 196. 1912. genus of Rhopalothriz.) Type: Rhopalothrix simoni Emery (by present designation). Odontopelta Emery. Genera Insect., Fasc. 118, p. 101. 1911. genus of Leptogenys.) Type: Leptogenys (Lobopelta) turnert Forel (monobasic). Pachysima Emery. Ann. Soc. Ent. Belg., LVI, p. 97%. 1912. genus of Sima.) Type: Sima ethiops F. Smith (designated by Emery). Parectatomma Emery. Genera Insect., Fasc. 118, p. 44. 1911. genus of Hctatomma.) Type: Hctatomma triangulare Mayr (designated by Emery). Pentastruma Foret. Entom. Mittheil., I, p. 51. 1912. Type: Pentastruma sautert Forel (monobasic). Phasmomyrmex Srtirz. Mitth. Zool. Mus. Berlin, V, p. 146. (Subgenus of Camponotus. ) Type: Camponotus buchnert Forel (monobasic). Physocrema Foret. Mém. Soc. Ent. Belg., XIX, p. 220. 1912. genus of Crematogaster.) (Sub- (Sub- (Sub- (Sub- (Sub- L9L0: (Sub- Type: Crematogaster inflata F. Smith (by present designation). Poneracantha Emery. Ann. Mus. Stor. Nat. Genova, XX XVIII, p. 548. 1897. (Subgenus of Hctatomma.) Type: Hctatomma (Poneracantha) bispinosum Emery (monobasic). Pristomyrmecia Emery. Genera Insect., Fasc. 118, p. 21. 1911. genus of Myrmecia.) (Sub- Type: Myrmecia mandibularis F. Smith (designated by Emery). Proatta Foret. Rev. Suisse Zool., XX, p. 768. 1912. Type: Proatta butteli Forel (monobasic). Promyrma Foret. Rev. Suisse Zool., XX, p. 764. 1912. Type: Promyrma buttelt Forel (monobasic). Promyrmecia Emery. Genera Insect., Fasc. 118, p. 19. 1911. genus of Myrmecia.) Type: Myrmecia aberrans Forel (designated by Emery). Psammomyrma ForeL. Mém. Soc. Ent. Belg., XIX, p. 237. (Subgenus of Dorymyrmez.) Type: Dorymyrmex planidens Mayr (by present designation). (Sub- 1912. WHEELER, ADDITIONS TO FORMICIDA 83 Stegomyrmex Emery. Ann. Soc. Ent. Belg., LVI, p. 99. 1912. Type: Stegomyrmex connectens Emery (monobasic). Terataner Emery. Ann. Soc. Ent. Belg., LVI, p.103. 1912. Type: Atopomyrmesx foreli Emery (designated by Emery). Tetramyrma ForEL. Rev. Suisse Zool., XX, p. 766. 1912. (Sub- genus of Dilobocondyla. ) Type: Dilobocondyla (Tetramyrma) braunsi Forel (monobasic). Trachymesopus Emery. Genera Insect., Fasc. 118, p. 84. 1911. (Sub- genus of Huponera.) Type: Formica stigma Fabricius (designated by Emery.) i eae ty if of ' in b py au * q 7 i | 4 = ris ar Wee Pee Ag Say bg ‘iat elit . 7.4 : , PGI iM AO fee eee hae vy, Hea? ry ve ti Coat ar Va hor ok Pet aie chin (lel ye vyi Vem ieme ty yee vec ay yen (oan rus" iti a ee ee BOl die und ae ge faite tate ety, | ; rigid ee flan ) vit vAHin ‘heempenele 4 ii amor aan ists i . ©) WP te a dh yer Fee Lit Oe yet Shed ae eve 7 ee Ma eA ee ii * J je) LU ha Paey a b i ) ; vr { ae ra A eft i 7a Wisi -a iy : We Spy ne nt ane an | aa 2 ie Pe Oe aa yn 4: mw ore oS a % E> y Pe - % “3 : ear re: fe y eS 4 rp E s PUBLICATIONS OF THE NEW YORK ACADEMY OF SCIENCES (Lyceum or Natural History, 1817-1876) The publications of the Academy consist of two series, viz.: (1) The Annals (octavo series), established in 1823, contain the scientific contributions and reports of researches, together with the rec- ords.of meetings and similar matter. 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The Annals are sent to Honorary and Corresponding Members desiring them. Subscriptions and inquiries concerning current and back numbers of _. any of the publications of the Academy should be addressed to THE LIBRARIAN, New York Academy of Sciences, care of American Museum of Natural History, New York, N. Y. — ANNALS OF THE NEW YORK ACADEMY OF SCIENCES Vol. XXIII, pp. 85-143; pll. EVI Kditor, Epmunp Otis Hovey A CONTRIBUTION TO THE GEOLOGY OF ____ THE WASATCH MOUNTAINS, UTAH BY Ferpinanp Frus Hinrze, JR. : NEW YORK PUBLISHED BY THE ACADEMY 12 Decemser, 1913 THE NEW YORK ACADEMY OF SCIENCES (Lycrum or NaturaL History, 1817-1876) ~ OFFIcERS, 1913 _ President—Emerrson McMiu.in, 40 Wall Street ~ Vice-Presidents—J. EpMUND Woopman, W. D. MartHEw CHARLES LANE Poor, WENDELL T. BusH Corresponding Secretary—HxEnry E. Crampron, American Museum Recording Secretary—Epmunp Otis Hovey, American Museum Treasurer—Heinry L. Donerty, 60 Wall Street Librarian—Ratpu W. Tower, American Museum Editor—Epmunp Otis Hovey, American Museum SECTION OF GEOLOGY AND MINERALOGY - Chairman—J. E. Yoopman, N. Y. University Secretary—A. B. Pactint, 147 Varick Street SECTION OF BIOLOGY Chairman—W. D. MattHErw, American Museum Secretary—WiLL1AM K. Gregory, American Museum SECTION OF ASTRONOMY, PHYSICS AND CHEMISTRY Chairman—CHarRLes LANE Poor, Columbia University Secretary—C. C. Trowsriper, Columbia University SECTION OF ANTHROPOLOGY AND PSYCHOLOGY Chairman—WeENDELL T. BusH, 1 West 64th Street Secretary—Rosert H. Lowiz, American Museum ‘The sessions of the Academy are held on Monday evenings at 8:15 o’clock from October to May, inclusive, at the American Museum of — Natural History, 77th Street and Central Park, West. [ANNALS N. Y. Acap. Sctr., Vol.. XXIII, pp. 85-143, pll. I-VI. 12 December, 1913] A CONTRIBUTION TO THE GEOLOGY OF THE WASATCH MOUNTAINS, UTAH? By FererDInanp Friis HIntTzx, JR. (Read by tatle before the Academy, 5 May, 1918) CONTENTS Page PRISED TIM centre tk gL hae AO eg aba Bib hee he AG Wien. ws MR Cw 86 TERMS yr aN ae a, itn edo at estas ai Nea lela De ccwl'y Seated whaneudke aie ale we i. MMEIMeR CMU OSA, MIOUMEAITIS. yc... cece 3 ole aiden Wclewewen weseeucde 87 Serene eevee MAT Gly UIUC ohh Sic. aia) aie, ich s.c.c lace Kebey o's wae Gas e siead slea'ea cme 88 meee aU Pe tN Re ai inl ie hares 8 bo Gis 06 aU icee vee see 6 e's WALA Mee oe eet 91 ENN RINNE Sor MCR dy este ect svete Siac aiaieidve.e Ce weirs iniele’e'ale je aside me aude 92 Sin ene COMP iP OVO NIG) 6c. wh cin xt ob: bs 're ids isc chkla GG n Sle e'e a lehe suela amleiewe aiacs 92 ear RENE N CLTEIUT Sits Sic Give ole dso six oa wlale s vie b duel eerie pave pieeisdlb.e a 93 Daa MmrAma IB ee EST TENG sche chap cP. =) 2) «aac So) 5 ae 4). elene'm v obs Sine hboe we Gasmeieete 94 Re eee OUP ESE CHION 1) ao bids) - sic v aveisg Woe ake se cceeceleiaadeeeew eee 95 ee MES ALES Reranch Tenia Vat Seve Par iaics Ge) ea. dies) o.ws0 es ,e.a oe ete ew Sw Rieleiw dees 95 eer eI TOA PCHEAIN.:...../60e.. wares oda ee eens ee wiieeeae 99 Origin and nature of the Algonkian sediments................05. 102 eI Raa Ronee RS fot vcd dicicee cic fet ora ic: alle iol wield fd Aw Gileper eo lao wie apd aie Bbw nd We 103 SM SOMME Te PNS eee tA aye in eka b Sy ahah oh id ein aye ce «abe. 'e wiv ele le wi¥'s © eles a ele ® 105 ERO col Pe CON Or gl GRU Re Soe a 105 rm PIE ENE Ne chong JW Set ocd as Cees) Sa eel Geshe les Ge sie a. POSSE PYAR A Sie ny 107 Rene Er Ss IE SUN eek PrN en nreeial ost Tel acs. a ur i dia a0 « (o,(\'6i 00 Giace! a average sikle a'% oca oie 108 SCREEN Pn anI SO NCL REEVENE fh g es ee vc faceh da cvs? si 0) u/cah wird loy'e."atelavm, ale! bee le @ierehalets a'at 109 Seeing Geen AAV GM, «52. sco als do é'ab-s. de Sha Pauwlds TPT oe He eR af 110 Ouray type of Devonian in the Central Wasatch................. 1 CI OME PEEVE LAA UE TIE AD re hs ek hacia ae lwo es oe Riera olin, IG did 0 bree eld ave, a8. wale 113 Unconformity between the Mississippian and Pennsylvanian...... 115 PEC GEC GION. o\sia-t ainte lara ate wie! ooea ea? 6's BSAA Oe ae CL Pe oe ery Pennsylvanian strata........... Rem MSTA Ete he imine lye hie Sra ping 120 eM EMI SCONE e Sots net, Gr cka ick iki ds Sidi bie pelpia Wie aineos aie ose cies a 120 Park City and sb go TESOL DS TOV Sie Cueto RU Ne and a eT 123 Seen SMM UD PETTITT PA DIO oa) iis cle lele sd ciel ccc ee des caw apcegsneretenus 126 PC ME hg odbc a dls vais oa vcd dale LER a hye chasers yay et A Se ties eee ae 127 Introductory rear en INI REPROD Re ie eters e Naru" Ge blela mele o: 8 7a éte a: eae! d ado ahw ese ete 127 ree PCE MCOTETAL VWWABELCH 0a cinis peisla wen swage cue escsviiaceducic 127 Peni MIT SERENA, cs ond a'sia se viels Sas sek aege aes ce samt aeke 128 nee RTE TP aha oe als vies dade eid eS caacn ce Ua knmeeepetades 130 Sma MneeT eer CRITTER oy Ge! ila ate y's,» 0\pe\ os «:'e (Wla'w Ae-a tums dws ees edie eles 133 Sine TR EOA Eee NOTED IE Toe crate fsa. n Wve Seve sa cise © <, wlald.b-die ale ore ¥e'wa we swe 136 Sen NEE sa, bers e Wat aie Ut twit ie hie tw ce cdcale's dre! tele Ow aierGei a) bweee aus ata 137 Oo Peer Ser Me ira lk silts 2 Nig wh Wibialeteidia Wiel’ wale wil slasiticwle come ae 138 1 Manuscript received by the Editor, 26 April, 1913. (85) 86 ANNALS NEW YORK ACADEMY OF SCIENCES Page Silver Work ‘fault: 006 vse cre ao ee ae ee ee 139 Minor faults ..ai. 2 ose eds 6 ao Saheede POO OC Cee eee 139 SUMIMATY. OF ‘CONCHISIONS ? 56... 2 Gaus es se ew wie eater oe ee eee 140 PHYSIOSTAPHY: «sc scus0-5 0-dhe Sw eros eames aw RRO ees, CELE eee 140 Straticraph yy. hss. 4.0% o's 6 ications eelece ys AU etOe te Ioae © ho aE enn ee 141 SEPUCHURE soso caa eles ow Gis ole Wie, clei lore erebouse ercberereten lece ehexolebetetete Pes. Marat oe ee 141 BIDMOSTAP AY sibs, 5. isis tie, 5 wis ns hs ome selves ca) le Lakers Paves Tenerelgol her ictekts eal erat see rekon ee 142 PRY SIOSTAPIY =o eis i dic ea SAGs Sawse ie ole eheete ak eset Saal RCE te ene ee eee 142 Stratigraphy and paleontology.....c. fhjciel. «cieteisieie faye eicne eons Ae en 142 Struchure: 452 6 ibe ask Boks et oie ein Renee eee SRS Bien ac 143 INTRODUCTION The general geological features of the Wasatch Mountains have long been known from the comprehensive reports of the early federal surveys. Since these general studies were made, several special problems have been investigated, with the result that many new facts have been added, in the light of which, many of the first conceptions have been greatly modified. One of the most important of these later observations is concerned with the structure. The complicated tectonic features of this remarkable range are only now beginning to be appreciated. The finding of large overthrusts in the vicinity of Ogden by Blackwelder in 1909 and the ‘tracing of the great Bannock thrust from southern Idaho south into the Wasatch range accomplished by Richards and Mansfield of the U. S. Geological Survey within the last year or two have added much impor- tance to this phase of the structure. Boutwell had previously discovered overthrusts in the Park City district, but they were thought to be local features and were not greatly emphasized. As might be expected, the unravelling of the structure has had an im- portant bearing upon the stratigraphy of the range, especially since the regions in which the overthrusts have been found were those that fur- nished the type sections to the early workers. The repetition of beds brought about by overthrusting escaped the attention of the Fortieth Parallel geologists, who gave the first unified account of the stratigraphy, and their section is therefore subject to correction. It is the purpose of the writer to present in this paper a number of facts that were observed in the summer of 1912 in the central part of the Wasatch range, particularly in Big and Little Cottonwood Canyons, and to discuss the structure and stratigraphy of that region. The dis- covery of a great overthrust at Alta, in Little Cottonwood Canyon, has HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 87 led to a new conception of the stratigraphy as well as the structure of this part of the range. The finding of many new fossil species has shed important light on the age of the paleozoic rocks, and the discovery of several disconformities has enabled the writer to subdivide the series into several new formations. Observations on the physiographic features of the central Wasatch have afforded interesting results on the present state of dissection of the Wasatch block mountain and have suggested an ex- planation of the principal drainage lines of the region. Other problems are partly solved, and much work will still have to be done before a com- plete account of the many interesting geological phenomena here shown can be given. The writer desires to thank the mining men of South Fork and Alta most heartily for the support and assistance which they generously ex- tended to him during his field work. While it does not seem possible to mention the names of all who have rendered help, the writer cannot for- bear to acknowledge the cordial treatment shown him by Mr. Green of the Tar Baby Mining Company and Mr. Barney of the Cardiff Mining Company in South Fork, and at Alta by Mr. Blake of the Columbus Consolidated, Mr. Lemmon of the Columbus Extension, Mr. Jacobson of the Alta Consolidated, Mr. Godbe and Mr. Burton of the Michigan Utah, Mr. Gabrielson of the South Hecla and Mr. Stillwell of the Emma. To the managers and directors of these mines, the writer is grateful for the privilege of visiting the various properties and studying the ore deposits. To the several members of the Department of Geology at Columbia, the writer feels greatly indebted for many helpful suggestions in the preparation of the report. To Professor Amadeus W. Grabau is due special thanks for the encouragement he has given from the very outset. Throughout the laboratory work, and especially on the paleontologic and stratigraphic side, he has manifested great interest in the results as they appeared. His kindly criticism has been of much value and assistance in formulating the conclusions here drawn. To Professors D. W. John- son and C. P. Berkey, the writer is indebted for many valuable criticisms relative to the physiographic and petrographic features of the work. PHYSIOGRAPHY ORIGIN OF THE WASATCH MOUNTAINS Immediately following Cretaceous time, the present Great Basin prov- ince was the scene of dynamic disturbances through which numerous mountain ranges were formed by the processes of folding and overthrust- ing. During early Tertiary time, the folds were truncated by erosion 88 ANNALS NEW YORK ACADEMY OF SCIENCES and the surface was reduced to an aspect of low relief. Then followed a period marked by profound faulting, the lines of movement being prin- cipally in a north-south direction, but with many cross fractures, which resulted in the formation of great fault-block mountains. These were characterized by relatively simple external features but with complex internal structure. The most easterly, and one of the most continuous of these fault-block masses, is the present Wasatch range. When newly formed, the Wasatch block had a steep western face and ‘a long gentle eastern back slope. It was greatly elongated in a north- south direction, extending from central Utah northward for almost 200 miles. ‘T’he width as measured from its fault face on the west to its eastern border was about 25 miles. Its height was mainly due to vertical displacement ‘along the great fracture line on the west. This dimension was no doubt cumulative and due to periodic uplift, the aggregate throw probably reaching 10,000 feet. The line of greatest elevation or crest of the block was near the western margin. DISSECTION AND DRAINAGE The dissection of such a block must have been initiated by the conse- quent streams which flowed down the two unequal slopes to the east and west. ‘The valleys developed by these opposed streams would thus ba transverse to the principal direction of the range, and when fully devel- oped would divide it into a series of roughly parallel east-west ridges on each slope, leading from the main divide to the two margins of the block mountain. The unequal declivity of the two sets of streams would in time cause a migration of the divide toward the center line of the block, if the structure and materials were not essentially different and the base levels were at the same elevation on both sides. If the base level on the east were higher than the one on the west, the divide would come to rest nearer the eastern border, and the valleys and ridges west of it would be longest and most prominent. Some of the most powerful streams on the west slope might even cut entirely through the divide and send out lateral. subsequent tributaries that would capture the east flowing consequents and lead them westward into the Salt Lake Basin. When once estab- lished, these master streams would continue to push eastward into the region beyond the Wasatch, gradually acquiring more and more drainage territory. In the light of these theoretical considerations, we may examine the present maturely dissected Wasatch block mountain for some of the larger features due to its original form and subsequent dissection. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 89 The main crest line of the Wasatch extends in a general north-south direction and stands at a variable height of from 3000 to 8000 feet above the level of the Bonneville Basin to the west. It is situated near the west- ern border of the block and is marked by a succession of lofty peaks which crown the western terminations of a series of ragged ridges that lead westward from the main divide. This divide is situated from two to six miles east of the crest line, being often nearer the eastern border of the range than the western. This is especially noticeable in the central Wasatch. Here the divide is also lower than the crest by more than a thousand feet. Hed HA FIG. 1. STEREOGRAM OF A PORTION OF THE CENTRAL WASATCH MOUNTAINS, UTAH NETSTAT, Shows a maturely dissected block mountain with a steep western fault face and a gentle eastward back-slope. The main gorges are Big and Little Cottonwood Canyons, heading near the eastern margin of the block, and representing principally obsequent stream channels. To the east, a similar series of ridges and intervening gorges lead off from the divide. A significant difference is to be noted here between the slope of the tops of the ridges east of the divide and those to the west. Kast of the divide, the ridges slope down to the level of high-lying basins, while westward they rise to the crest line and then suddenly break off to the Salt Lake plain. The tops of the ridges from the crest eastward descend gradually to the divide, and, crossing over it, they continue to become lower until they reach the eastern valley levels. They thus indi- cate the original back slope of the block, though they do not preserve any of the undissected upland surface. ‘The present eastward slope of the ridge tops is not a very noticeable feature when viewed from the high peaks on the crest, the inclination being but a few degrees and appearing almost horizontal to the eye. From the more rapid erosion that has been going on along the crest line, however, it is safe to infer that the original back slope was of greater inclination, probably as much as 10 or 15 degrees. 90 ANNALS NEW YORK ACADEMY OF SCIENCES The migration of the divide from the crest line toward the eastern margin of the block is most pronounced in the central part of the range. Big and Little Cottonwood canyons are good examples of long and deep valleys pushed back from the western face of the range well toward its eastern margin. The streams which have cut them have a more direct course to the base level of the region than those on the opposite side of the divide. This advantage has enabled them to send the divide east of the center line, where it should be expected to come to rest if the stream grades were equal in both directions (see Fig. 1). At present, the Salt Lake Basin is the base level for the drainage of the east slopes as well as the west. The two through going streams, the Provo and Weber Rivers, bring the eastern drainage by long round-about courses back into the Bonneville Basin. No special field work has been done by the writer to determine the conditions which have established these streams in their present courses, but the thought suggests itself very strongly that they began as Big and Little Cottonwood creeks did to cut headward, and being more successful penetrated far enough to capture all of the eastern drainage of the central Wasatch and much of the western Uintas and the plateau region to the north and south of the Uintas. Their headwaters approach each other very closely at the western end of the Uinta uplift and are here separated by a low divide near the southern limit of the Kamas prairie. This divide becomes more pronounced as we follow it westward, rising as a high ridge between Parley’s Park and Provo, or Heber Valley, and eventually culminating in Clayton Peak on the Wasatch divide, at the head of Big Cottonwood Canyon. The eastern slope of the Wasatch in this neighborhood is thus drained by two river systems which lead off in opposite directions, at length turning westward and cutting across the Wasatch to the Bonneville Basin. The small con- sequent streams which lead north-east and south-east from the Wasatch divide on opposite sides of Clayton Peak have the disadvantage of a long detour to the base level and have therefore been unable to cope with the streams west of the divide which have a much shorter and more direct course to the same base. Structure and hardness of the rocks seem to have exercised only a minor amount of control in the determination of the position of the stream channels west of the divide. In Big Cottonwood Canyon, where the hardest rocks of the region are exposed, the stream seems to have cut indifferently across the beds in a peculiar diagonal fashion in the lower half of its course. In the upper half, it has much less fall and follows the strike of the beds more closely. The rocks here are limestones, shales HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 91 and sandstones, while in the lower and steeper part of the canyon they pass into hard quartzites and slates. It thus seems to be a fact that the structure and hardness of the rocks in the upper part of the canyon have had a somewhat greater influence on the course of the stream than in the lower part. Little Cottonwood Canyon is developed for the most part in granite of a very hard and homogeneous character. The course of the canyon is parallel to Big Cottonwood, where both structure and heterogeneous rocks enter into the problem. It is apparent that there must be some other cause operative to produce the correspondence. The chief determining factor seems to have been the original form of the block mountain. The western conse- quent streams on the steep fault face developed their channels transverse to the main north-south trend of the block, their direction being deter- mined by the slope primarily. If the block was rapidly uplifted, the high gradient of the streams would be quite sufficient to cause them to cut back independent of the structure and kinds of rock. The direction of back-cutting would be at right angles to the front of the block, and as this was somewhat irregular, being curved in places, the stream courses should show some irregularity in direction. This indeed is the case. Where the fault face forms a great curve, as it does southeast of Salt Lake City, the canyons show a marked tendency to take off in the direction of the extended radii of the arc, as should be expected. GLACIATION After the Wasatch block mountain had been maturely dissected by stream action as briefly outlined above, Alpine glaciation set in during the Pleistocene period. Many of the deep V-shaped gorges were hollowed out into broad U-shaped valleys of striking outline. The best known ex- ample is Little Cottonwood, but there are many others in the upper parts of the large canyons. The upper half of Big Cottonwood is a deep U- trough with many hanging valleys on both sides. The heads of the can- yons were widened into broad catchment basins with steepened sides. The divides were greatly sharpened in many places. Altogether, the topography was modified to a considerable extent in the central Wasatch, especially at the higher elevations near the heads of the canyons.2. Nu- merous lakes due to glacial damming and the plucking action of the ice by which rock basins of considerable depth were formed are to be found at the heads of the larger canyons. Good examples of roche moutonneés, 2For a map showing the location of the principal glaciers and their catchment basins, as well as a brief account of the glaciation in the Wasatch, see ATwooD: U. S. Geol. Surv. Prof. Pap. No. 61. 92 ANNALS NEW YORK ACADEMY OF SCIENCES rock steps, and various other features due to glaciation are of frequent occurrence (see Plate I, Fig. A). Since the disappearance of the glaciers, erosion has been slight. The streams have cut through the loose moraines in some places, but where they have been flowing on solid rock beds, they have cut but faint notches. These modifications are negligible as compared with the preglacial and glacial erosion which produced mature dissection. STRATIGRAPHY INTRODUCTORY STATEMENT The first works of importance on the general stratigraphical succession in the Wasatch Mountains are those of the King* and Hayden* surveys in the late seventies. They are to-day the only comprehensive account that we have dealing with the great range of sediments there exposed. Being general in their treatment, they have left many details to be sup- plied by closer investigations, such as are carried on within smaller quad- rangles where the necessary time is taken to work out structural problems as well as to observe the general sequence of beds. American stratigraphy offers many examples of the mistakes that are so easily made by follow- ing the law of superposition without due regard to structure. Unrecog- nized repetition of beds by folding and faulting has often led to serious errors in estimating the real thickness and succession of formations. Within the limited time that was allotted to the comparatively few workers on these early surveys, a wonderful amount of field work was done, and magnificent reports, well illustrated with maps and sketches, were issued, which, though they are now known to be wrong in many cases, still serve as the best introduction to the systematic geology of the range. In presenting a generalized account of the stratigraphy of the Wasatch Mountains, the Fortieth Parallel geologists seem to have taken the sec- tions which showed the thickest development of the rocks of the various systems. The sections exposed in Weber Canyon and a few miles to the north in Ogden Canyon, together with those found in Big and Little Cottonwood Canyons, sixty miles to the south, seem to have been chosen as the types for the Paleozoic rocks. Especially the latter seems to have made a wonderful impression upon King, who introduces it thus: “I will now give a section observed between the mouth of Cottonwood Canyon 3U. S. Geol. Expl. 40th Par., vols. I and II, 1877, and Vol. III, 1878. 4U. S. Geog. and Geol. Surv. of the Territories. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 93 and Parley’s Park, the most extended and instructive stratigraphic ex- hibition of the Paleozoic series in the Fortieth Parallel area.” ° It now appears that the Ogden area, recently visited by Blackwelder® and some of his colleagues from the University of Wisconsin, and the Cottonwood Canyon district, covered by the writer last summer, are simi- larly characterized by complicated structures involving large overthrusts which duplicate the rocks of the lower members of the Paleozoic series and give an apparent thickness which is much too great. Blackwelder has shown that the Ogden quartzite of Hague and Emmons does not exist as originally defined. Elsewhere in this report, it is shown that the Ute Mill Creek Canyon Big Cottonwood Canyon NE A "ep “ 3 y, 4 oe? - AY ‘ 4s by” y g GPa 240 4 Lope 7, p ‘ Vs OEP SP % if 44,744 yes Ae X97, ae: a3 2G 7277 Y, Y, ALi OO L- M B OLAS. SB We Ra We Pus Pr Pwq’ B.O¢ FIG. 2, SECTION EXPOSED BETWEEN THE MOUTH OF BIG COTTONWOOD AND THE HEAD OF MILL CREEK CANYONS Al = Algonkian. C=Cambrian. O=Ordovician. D=—=Devonian. M = Mississip- pian. Pwq=Penn. Weber quartzite. Pp=— Penn. Park City formation. Pws = Per- mian Woodside shale. Tt= Triassic Thaynes formation. Ta— Triassic Ankareh shale. Jn= Jurassic Nugget sandstone. limestone of supposed Silurian age also has no existence as such in the central Wasatch, but is in reality the lower part of the Wasatch limestone reported as belonging to the Carboniferous. It seems strange that this relation should not have been discovered by the early workers on account of the marked contrast between the sequence of beds near Alta in Little Cottonwood Canyon and that seen across the divide to the north in Big Cottonwood Canyon. BIG COTTONWOOD SECTION At the mouth of Big Cottonwood Canyon is exposed the base of the great section of Paleozoic and Mesozoic rocks above referred to by King. Beginning on the strike of the beds which stand at a high inclination 5C. KING: U. S. Geol. Expl. 40th Par., Sys. Geol., Vol. I, p. 165. 1878. ®E. BLACKWELDER: “New Light on the Geology of the Wasatch Mountains, Utah,” BullG S.A. Vol, 21, pp: bL7-b42.- 1910: Q4 ANNALS NEW YORK ACADEMY OF SCIENCES (dip N. 60°), the great canyon holds a general course N, 70° EH. for nearly eight miles, slowly truncating the edges of the successively higher beds, which as we go east gradually change their strike toward the south. From its mouth for a distance of about six miles, the canyon is walled by brown and yellowish quartzites interspersed with thick beds of black and purplish blue slates. The upper six miles of the canyon show the post- Cambrian formations, the general continuity of the beds being seriously broken only at one point, opposite South Fork of Mill D. The top of the section passes beyond the northeast divide of the canyon into the north- west corner of the Park City district. QUARTZITE-SLATE SERIES The great quartzite and slate series is succeeded below by gneiss and schist or granite. The igneous nature of the granite contact was not rec- ognized by the Fortieth Parallel geologists, who mapped the granite as Archean and described the contact as one of sedimentary unconformity. The quartzite succession was assigned to the Cambrian, including the lowermost exposures. In describing the rocks referred to the Cambrian - in his recapitulation of the Paleozoic, King’ says: “Thus far among the reported occurrences of the rocks of this horizon in the Cordilleras, the locality at the mouth of Big Cottonwood Canyon must remain as the finest example and the stratigraphical type. The lowest member—the Cottonwood slates, a group about 800 feet thick, which here rests upon highly metamorphic Archean schists—has thus far yielded no organic forms. The rocks are dark blue, dark purple, dark olive green and blackish argillites, all highly silicious and as a group sharply defined from the light-colored quartzite schists which conformably overlie them. This second group, by far the greatest of the whole Cambrian series, is a continuous zone of schists which have a prevailing quartzite character, though varied with considerable amounts of argillaceous matter. From 8000 to 9000 feet thick, it has a general uniformity of lithologic condition from bottom to top. . . . The prevailing colors of this member are gray, greenish gray, drab and pale brown, never dark colors. Conformably overlying it are 2500 to 3000 feet of cream and salmon color and white quartzites and quartzofelsites. Occasional sheets of conglomerate are seen in the quartzites not far below the summit of the Cambrian.” A few years later, in the course of his studies of the Cambrian sections of the Cordilleras, Dr. C. D. Walcott® visited Big Cottonwood Canyon, examining the quartzite series in more detail and re-measuring the sec- 7™C. Kina: U. S. Geol. Expl. 40th Par., Vol. I, pp. 229-230. 1878. 8C. D. WaLvoTTr: “Second Contribution to the Studies on the Cambrian Faunas of North America,” Bull. U. S. Geol. Surv. No. 30, pp. 38-39. 1886. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 95 tion. Walcott’s section® is invertedy as originally published, and is here given in the natural order, as follows: Big Cottomwood Section Feet 14. Superformation: Mixed sandy and calcareous rocks which rest con- formably on 138 of the section and carry a fauna which refers it to the lower Silurian (Ord). 13. Hard, silico-argillaceous shales, a little sandy in places............. 250 Fossils: At the base, Cruziana sp. associated with Olenellus gilberti; 100 feet higher up, a band of shale afforded Linguella ella, Kutorgina panula, Hyolithes billingsi, Leperdita argenta, Ptychoparia quadrans and Bathyuriscus producta. Pesta y GOMpPACL GQUATUZILIC SANGSTONE: 6.0.60 cee ee Stk cee ec we eacae 3,000 11. Purplish and reddish brown quartzitic sandstone...............0... 75 Pe fea COMpACt-OUartAZILiC: SANGStONE. ..ou0 ce ase aN else Seles cle cweeneceses 700 9. Black, sandy, arenaceous, slightly micaceous shale................. 15 8. Light gray quartzite and quartzitic sandstone, in layers varying from 10 feet to 2 inches, the thin layers occurring as partings between the more massive bands of layers. In some places, the quartzitic sandstones show grains, and in others they are lost. Stains of purple, iron rust, reddish brown and buff color occur............. 2,700 . Arenaceous and argillaceous slates, black, bluish black, drab and yellowish green. The exposure is extensive, the opportunity for finding fossils excellent, and the slates afford a beautiful matrix for their preservation, but none were oberved...............c.cece. 700 6. Light gray quartzite and quartzitic sandstone, in layers varying from 10 feet to 2 inches. In some places, the quartzitic sandstones show grains, and in others they are lost. Stains of purple, iron rust, =] Remit, PEOW iN 4200 WU COOP OCCU arc <0 «acs wie ole, se is éataleva eons oie 200 5. Hard, black, arenaceous shale, with specks of mica on the surfaces. Quartzite and shale intercalated near the base.................2.. 1,000 4. Light gray quartzite and quartzitic sandstone in layers, varying from 10 feet to 2 inches. In some places, the quartzitic sandstones show grains, and in others they are lost. Stains of purple, iron rust, Festian, bowie nO” Bile (COlOT (OCCII oss ccc ce x vie aoc ce eles ae os tba e ns 700 3. Purplish, thin bedded sandstone, with bands of greenish yellow argil- PICeOte ssh ee Nene TAGeSTMMNING s. f ANNALS NEW YORK ACADEMY OF SCIENCES In an outcrop considerably higher up, stratigraphically, but almost completely covered so that it was somewhat doubtfully in place, two specimens of the following well-known Ouray limestone type were ob- tained: Camarotechia endlichi Meek Of the above species, the ones having the widest range are Huomphalus and Spirifer orestes var. wasatchensis. Huomphalus utahensis, 2. lavus and #. ophirensis have commonly been described as Mississippian from their resemblance to the Waverlyan species of the Mississippi Valley. Their association here with a Devonian fauna, and their range practically from the bottom to the top, indicates that they are probably older than Mississippian, though they may have persisted in other sections into the lower part of the Mississippian. It would otherwise be necessary to assume that the Devonian forms had survived till the Mississippian in order to explain this association, but this seems hardly warranted from the occurrence of Hunella linkleni Hall and Cystodyctia gilberti Meek which are described elsewhere as coming from the Middle Devonian (Lower Hamilton of Ohio). In looking for the equivalent of this fauna in the West, that of the Ouray limestone in western Colorado suggests itself both from its prox- imity and its striking faunal resemblance. Kindle,?? who has described the Ouray fauna and has done more than anyone else in suggesting a correlation of the western Devonian strata, has the following to say: “Camarotechia endlichi may be considered the most characteristic species of the Ouray fauna, for it has been found at practically every outcrop where the fauna has been recognized from northern Colorado to southern New Mexico.” The occurrence of this widespread species in the central Wasatch has brought the western border line of the Ouray fauna nearly 200 miles west of the western boundary of Colorado, which Kindle believed to mark its western limit. While the outcrop from which the Wasatch repre- sentatives were obtained was poorly exposed and their associates were not discovered, they may nevertheless be present in the Wasatch region, and later search should reveal them. The presence, however, of this most characteristic species is, it would seem, sufficient to indicate the equivalency of the two formations. Moreover, the resemblance of the faunas that were found below the endlichi horizon to the Upper Devonian fauna of Iowa points to an eastern connection rather than one with the Jefferson limestone of the West. 2H). M. KINDLE: Bull. Am. Pal., Vol. 4, No. 20, p. 20. 1908. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH i a The stratigraphic relations of these beds to the ‘underlying non-fos- siliferous limestones provisionally assigned to the Ordovician is one of disconformity. The beginning of Devonian sedimentation is very clearly marked by a limestone conglomerate which rests upon a thin bed of yellowish-green shale, which in turn rests on a thick limestone member. This condition is best shown on the Reade and Benson ridge, just above the old mine workings of the same name. It is also exposed on the ridge between Day’s Fork and Little Cottonwood Canyon, just west of Flag- staff Mountain. No angular discord between the beds above and below the break could be detected, though the presence of the hiatus is phys- ically indicated by the unmistakable conglomerate. Upward, the Devonian strata seem to be continuous with the succeeding Waverlyan limestones. In this respect again, the central Wasatch is like the Colorado and New Mexico areas where deposition is thought to have proceeded continuously from the Upper Devonian into the Mississippian. From the occurrence of these limestone beds on the Reade and Benson ridge, the name Benson limestone is proposed to designate the part be- longing to the Devonian. They range as above stated from Middle to Upper Devonian and are succeeded by Lower Mississippian limestones — without any observed disconformity. MISSISSIPPIAN STRATA Rocks of Carboniferous age have been known from the Wasatch Moun- tains and the Great Basin region since the first explorations of Captain Stansbury in the early fifties. It was left, however, to the Fortieth Parallel geologists to give them a name and describe their stratigraphic relations, thickness and distribution. King applied the name Wasatch limestone to a succession of strata 7000 feet thick and composed mostly of limestones supposed to be of “sub-Carboniferous” age. Aside from the fact that this name was preoccupied for a Tertiary formation, it is now known that the original Wasatch consists of several stratigraphic members, ranging in age from Ordovician to Mississippian. In the northern Wasatch, the Paradise limestone of Silurian age and nearly a thousand feet of limestone identified by Kindle as the equivalent of the Jefferson have been separated from the lower part of the Wasatch. The rest has been regarded by Girty as Lower and Middle Mississippian, the lower division probably correlating with the Madison limestone. It seems advisable, therefore, to discontinue the use of the name Wasatch limestone as employed by King. In the central Wasatch region, the Mississippian strata admit of a three-fold subdivision into a lower limestone series with a Productus 114 ANNALS NEW YORK ACADEMY OF SCIENCES fauna, a middle sandstone and shale, apparently barren of fossils, and an upper limestone series which is very fossiliferous. These beds are well exposed in Big Cottonwood Canyon at the northern end of the Reade and Benson ridge which separates South Fork from Day’s Fork. At Green’s Hill in South Fork, the lower limestone can be traced across the canyon from east to west. From the cliff which rises on the west, the following forms were obtained : Productus semireticulatus Productus cora Derby@ sp. Hapsyphyllum sp. The sandstone and shale which overhe this limestone member were not well exposed within the district, usually forming the bottom of gulches because of their poorer resisting qualities to weathering and being largely covered with talus and soil. No fossils were found in them, but they may have been overlooked because of poor exposures. The sandstone, where seen, is composed of much angular material giving it the aspect of a breccia. The prevailing color of the sandstone is light yellow, straw color, while the shale which overlies it has a reddish tint. It is an interesting fact that Blackwelder has noted a similar occurrence sixty miles to the north, in Ogden Canyon, and several localities there- abouts. The exposures there are apparently better and have been care- fully described. Lavender and maroon shales with abundant sun-cracks filled with mud and sand and the same brecciated appearance are noted. From these and other characters, a continental origin is suggested, the necessary conditions being found on the surface of deltas of flat gradient in regions which are either generally or seasonably arid. The presence of this non-marine member within the Mississippian was not noted until it was discovered in Ogden Canyon by Blackwelder?* in 1910, and its recognition in Big Cottonwood Canyon by the writer gives it a much wider distribution and importance as a stratigraphic unit. It will, no doubt, partly account for the limited development of the Mississippian rocks in the Wasatch Mountains. In this connection, the unconformity at the top of the over-lying thin-bedded limestones is of great importance. As will be shown, this represents a great interval of time during which much of the Upper Mississippian must have been removed by erosion. From the fossiliferous portion of the limestone immediately below this break, the following forms were obtained : 23. BLACKWELDER: “New Light on the Geology of Wasatch Mountains, Utah,” Bull. G. S. A., Vol. 21, pp. 528-529, 1910, HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 115 Caninea cylindrica Scouler Spirifer striatiformis Meek Dielasma attenuatum Martin Seminula subtilita Spirifer rockymontanus Productus semireticulatus Phyllipsia cf. trinucleata Herrick Amplexus sp. Orbiculoidea newberryi Spirifer sp. nov. Caninea cylindrica is a well-known European species and so far as the writer is aware has not been recognized before in America. It is char- acteristic of the middle part of the Lower Carboniferous in Belgium and the region about Bristol, England. Probably next in importance is Spirifer striatiformis which is very abundant in the Cottonwood region. It likewise points to the Middle Mississippian. By far, the most abundant form is the great coral Caninea. The in- dividuals lie closely packed together in a layer about three feet thick, being very firmly cemented together with a siliceous clay which has be- come exceedingly hard. They were discovered by the writer in the early part of the season, and it was thought that they would make an easily recognizable reference horizon on account of their abundance and size, but while their general position was located in many places, no other occurrence was found. Immediately overlying this coral bed is the basal Pennsylvanian con- glomerate made up of rounded chert pebbles and silicified corals together with much fine material. This erosion surface truncates the lower beds, as may be inferred by the absence of the coral layer in all other places within the district except the one in which these interesting forms were first discovered near the. mouth of South Fork. Careful observation seems to indicate some difference of dip between the upper quartzite beds and the lower limestones. The relation, therefore, is one of low angular unconformity. Unconformity between the Mississippian and Pennsylvanian There can be no doubt that there exists an unconformity at the top of the Mississippian in the Cottonwood section. The occurrence of a similar break farther to the north has also been reported by Blackwelder?‘ at the base of the Morgan formation. He says: “The lower limit of the formation (Morgan) is sharp, for the earthy red sandstones rest upon % Op. cit.. pp. 529-530. 116 ANNALS NEW YORK ACADEMY OF SCIENCES a cavernous weathered surface of fossiliferous gray limestone. Just above the contact lies a coarse sandstone which consists of well-rounded frosted sand-grains bound in a deep red matrix and including bits of limestone and black chert from the underlying series. Although the bedding of the Morgan formation is essentially parallel to that of the limestone below, the relations here clearly indicate a disconformity, sig- nifying an erosion epoch between the Mississippian and the Pennsylva- nian.” From faunas obtained above the disconformity, which show close relationships, the erosion interval is thought to be geologically brief in that region. | Dr. C. P. Berkey”® has also described an unconformity at the base of the Weber quartzite in the western Uintas. He says in part: “The base of the overlying formation, chiefly quartzite, is a true basal conglomerate. There are abundant fragments and pebbles and boulders from the cherty limestone bed immediately below, and in some places the finer cementing or filling matter is calcareous rock flour (calcilutite) and granular limestone (calearenite) and chert (silicarenite). Fossils are abundant below the break but rare above it in this area. From the above, it is certain that there is an erosion disconformity in the Upper Carboniferous of the Uintas that marks moderate readjustment of levels, so that the strata are not perfectly conformable in angle, although the later folding of the range has been so much more profound that this is lost sight of except along the immediate break.” In the western Uintas, there are two strongly developed quartzites. Barring discrepancies in thickness and noting only succession, the upper- most one of these would appear to correspond to the true “Weber.” ‘The erosion break occurs here at its base. While Berkey puts the discon- formity into the Upper Carboniferous, he establishes the fact that it occurs below the Weber quartzite, which corresponds exactly with its position in the Big Cottonwood section. Many of the details of descrip- tion also correspond, such as the prevalence of cherty pebbles and much fine material and slight discordance of dip between the upper and lower layers. An absence of fossils above the break in these two sections is also significant. In the northern Wasatch sections at the base of the Morgan formation, fossils occur in limestone layers, showing, according to Dr. Girty, that the unconformity there corresponds to a brief time interval. 'T’o decide the value of the unconformity, 1t is only necessary to find a section not too remote which shows no break and compare it with the Wasatch sections and Berkey’s western Uinta section. Such a one is to be had at Mercur in the Oquirrh Mountains. “Al Oya Ed BERKEY : “Stratigraphy of the Uinta Mountains, Utah,”’ Bull. G. S. A., Vol. 16, pp. 524-527. 1905. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 117 Mercur Section In Lewiston Canyon, at the head of which is the little mining town of Mercur, there is exposed a great anticlinal fold, the axis of which runs northwest and southeast, somewhat diagonal to the general trend of the range, which is north-south. Lewiston Canyon cuts directly across the fold, exposing the anticline on both sides of the canyon. ‘The lowest rocks brought up are of Lower Carboniferous age, and the highest ex- posed, directly over the axis of the fold, are also of that age. The crest of the range to the east rises on the east limb or flank of this anticline, and here are exposed the rocks of Upper Carboniferous age. The section thus exposed is as follows: leet Pataer anhercalated S@TICS. ..5.0.0......0s cee eee scecescceaeses D,000-6,000 Rae RTT PITMESTONG 20s sicsays she os omic le He bie wisls'acn wltewaseeswadsicanleed 5,000 eT Me rcalated: SETICS: . ..)00 6 2 ches ce bee coe skew see es ele see eles 600 Sere TPT FIFE UOTE. fr5, 2 cicceds ea. ksd'e overs she suas ajo Ba bee G6 bw es elaine ce 200 Above the Upper Intercalated series comes the great Weber quartzite 8000 feet thick exposed on the eastern slopes of the Oquirrhs at Bingham and northward. Below the Lower Blue limestone, in Dry Canyon, which parallels Lewiston Canyon on the north, are several hundred feet of Lower Carboniferous limestone, below which come 2000 feet of Devonian, Silurian, Ordovician and Cambrian strata. There is thus a great series of sediment exposed in these three localities ranging from the Cambrian to the Upper Carboniferous. Fossils obtained from the Lower Blue limestone by Mr. Spurr,”® and examined by Professor Schuchert, were found to be of Mississippian age. The limestone is a dark blue, semi-crystalline rock, in which zaphrentoid corals seem to be the most abundant fossils. Above the Lower Blue comes the Lower Intercalated series, 600 feet thick, the lowest member of which is a sandstone 100 feet thick. Above this come frequent alternations of siliceous and calcareous sediments (silicilutytes and calcarenytes). T'wo paralle] sections measured on the steep bare walls of the canyon three-fourths of a mile apart showed con- siderable thinning of these beds toward the east, even in this slight distance. Above these intercalated beds is a great limestone succession 5000 feet thick, broken only in two places by very dark calcareous shales, one about a thousand feet below the top and the other about the same distance from 2% J. E. Spurr: “Geology of Mercur District, Utah,’’ U. S. Geol. Surv., 16th Ann. Rept., Part tl, pp. 3ti-3tT. 1894. 118 ANNALS NEW: YORK ACADEMY OF SCIENCES the bottom. From the lower shale, a bryozoan and brachiopod fauna was obtained, which Professor Schuchert assigned to the Burlington-Keokuk horizon, The upper limit of the Great Blue limestone merges gradually into the Upper Intercalated series, which, with its frequent alternations of siliceous and calcareous beds, is In sharp contrast with the heavy blue layers of the Great Blue limestone. Between these two formations, Schuchert places the division between the Carboniferous and Mississip- pian. The Mississippian in the Oquirrhs is thus made somewhat over 6000 feet, and the upper division, counting the Weber quartzite exposed at Bingham and over a large area to the north, between 15,000 and 18,000 feet. To facilitate the discussion and bring out the relationships which exist among the Carboniferous formations of the Oquirrh, Wasatch and Uinta mountains, columnar sections from these three ranges taken in an ap- proximate east-west line through the Cottonwood district have been drawn side by side in Fig. 4. The distance between Mercur and Big Cottonwood Canyon is about equal to the distance from Big Cottonwood to the western Uintas, being in the neighborhood of thirty-five miles. The much greater development of Mississippian and Pennsylvania strata in the Oquirrh Mountains is seen at a glance. The corresponding parts are indicated by the dotted lines. It becomes apparent at once that the unconformities shown in the Wasatch and Uinta sections represent a long interval of erosion. Farther to the east, in Colorado, this same unconformity has been reported between the Mississippian and Pennsyl- vanian formations, and the same explanation no doubt applies there as well. It seems reasonable to suppose that the Mississippian was repre- sented by much thicker formations in these sections at the beginning of Pennsylvanian time than is shown at present. The Great Blue limestone was very probably represented in them all, but just when the area of the Wasatch and eastward into Colorado was lifted and exposed to erosion — cannot be definitely stated. It was probably toward the end of Great Blue time. During the long period of erosion which followed, most of the Mississippian limestone was worn away and transported elsewhere to be deposited as calcareous mud or, if dissolved, remain in solution in the sea water. The new shore line receded westward until it came to occupy some position between the Wasatch and Oquirrh mountains. Here it seems to have remained for a long time, as we may judge from the nature of the great deposits which formed in the Oquirrh Mountain area. Above the Great Blue limestone, we have the Upper Intercalated series, which on the Mercur side of the divide is from 5000 to 6000 feet thick, but it continues east of the divide and may be as much as 10,000 feet in SNIVLNNOW HYYINDO AHL NI 3NIVA SLI GNV ‘SNIVLNNOW VLNIN GNV HOLVSVM 3HL NI ‘S4IN ysainbo NVINVA7ASNN2d ONY NVIddISSISSIN ZHL NSS3MLAG ALINYOJNOONN LVSYD J3HL MOHS OL SNOILOSS ‘Ph ‘DI4 YUpif ‘ANoaW 1% Bs) HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH auojsawi| an|g 4am07 p2yvjo2424U | 42M07] "SULAI YOADSOAA ‘S4IN eo LUIN uohuny poomuoj0y big (ud14 W096) y) PS = = — ajeus PLY —— 000S QU0}soUs!| ani 70045 snyzoly yoy F @UOfs JULI) UOSUaY UO!}OW104 appoy FI | ah S| (haysag y jorsaquy Uo0|s01q PRIA -- — -- — ~~ — fia ryoyuaa Uy Fo27G PRR e4iZponb saqan |= ,0009-0005 p24zo|pI123,u| 4addr) UO!}PULOF hyy ysoy 2{DYS Apispooa Ha as 4994 000¢ 0002 000! 0 eu ,9006 == ayiZpubnb sagan li: UDIUDAIASU Ua upiddississi},} 120 ANNALS NEW YORK ACADEMY OF SCIENCES thickness before the Weber quartzite is reached. This series is described as consisting of numerous alternations of sandstones and sandy limestones. many of the beds presenting for considerable distances complete inter- mediate stages between the more calcareous on the one hand and the more arenaceous on the other. ‘The presence of marine fossils through- out the series, in the more calcareous layers, may be taken as good proof that the deposit was formed in the sea and probably not far from the shore. The lime muds from the great limestone area toward the east became mingled with the sands of the shore, giving rise to the calcareous sandstones which are so prominent a part of these intercalated beds. The Mercur report leaves much to be desired in the matter of details concerning the organic record. With the excellent exposures to be had there and the obvious importance of knowing what fossils are imbedded in these rocks, it is to be hoped that this section will soon receive the careful study which it deserves. Enough has been done, however, to de- termine the age of the series as a whole, and to warrant the comparison that is here made. Following Spurr’s report, we may assume that depo- sition was continuous in the Oquirrh Mountains. The hiatus, therefore, in the Wasatch and Uinta sections, represents a long erosion interval, comparable in time to the period necessary for the deposition of the 6,000 to 10,000 feet of intercalated limestones and sandstones. It seems also probable that it was even much longer, as will be brought out in the dis- cussion of the Weber quartzite problem (see Fig. 4). PENNSYLVANIAN STRATA Weber Quartzite Following the basal Pennsylvanian conglomerate in the Big Cotton- wood section is a quartzite 1000 feet thick, in which no fossils were found. The sand grains are of fairly uniform size, giving a rock of even, rather fine-grained texture. The bedding is prominent and regular -in layers of moderate thickness, While the surface has a brownish ap- pearance, the freshly broken rock is quite colorless. Ripple marks, cross- bedding and other shallow water characters seem singularly wanting, yet the fine detrital nature of the deposit certainly points to shallow water deposition. In the upper portion, thin limestone layers are intercalated between the sandy beds, and a succession of mainly cherty blue and white limestones follow, making up several hundred feet in thickness. These are well exposed on the north side of the canyon, just opposite the gov- ernment forest station. Above these limestone beds, the quartzites reap- HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 131 pear and give another thousand feet of fine-grained white rock. The series thus defined above the disconformity which terminates the Missis- sippian strata constitutes what is here called Weber quartzite. In the Park City district to the east, Boutwell?* reports only the upper portion of the Weber quartzite as seen in outcrops. “The middle and basal portions of the formation, which are not present in this area, outcrop in prominent cliffs just south of the district. Except for a few thin limestone beds near its top, the middle portion is massive quartzite, but in the lower part, the intercalated limestone members increase in number and thickness.” The middle and basal portions here mentioned correspond with part of the upper and middle parts of what is called Weber quartzite in this report. The thickness given in Boutwell’s section is 1350 feet, which he regards as too small and gives a tentative estimate of 3500 feet. The exact thickness is still doubtful, as continuous exposures could not be found within the Cottonwood district, but 3500 feet is probably too great. Somewhat more than 2000 feet is thought to be more nearly correct. In the type locality in Weber Canyon, 30 miles to the north, the For- tieth Parallel geologists?* have given the thickness as 5000 to 6000 feet. This figure has been questioned by Blackwelder,?® who follows Weeks*® and separates the lower red beds of that section from the Weber and calls them the Morgan formation. There is, however, no doubt that the de- velopment of the Weber quartzite in Weber Canyon is considerably greater than in Big Cottonwood and that the thickness is subject to variation from place to place. In less than 15 miles north of Weber Canyon, it disappears altogether and the Park City limestone which overlies the Weber in all of the southern sections rests directly on Mis- sissippian limestone. Blackwelder describes the unconformity as one of low angular discordance, the beds of early Mississippian age being slowly truncated, over the edges of which the Park City limestone rests. As we go southward, the Morgan formation and Weber quartzite appear be- tween the Mississippian limestone and Park City formation. The Park City beds thus overlap the Weber quartzite and Morgan red beds, and going still lower rest on early Mississippian. It is also important to note that in Weber Canyon, the Morgan forma- tion rests on much higher Mississippian beds than in the northern sec- tions. This fact may be explained in several ways. The presence of a 27 J. M. BOUTWELL: U. S. Geol. Surv. Prof. Paper 77, p. 45. *C. KinG: U. S. Geol. Expl. 40th Par., Vol. I, p. 161. 2H. BLACKWELDER: Op. cit., p. 531. °F. B. WEEKS: Unpublished report of U. S. Geol. Sury., quoted by Blackwelder. 1908. 129 ANNALS NEW YORK ACADEMY OF SCIENCES widespread unconformity between the Pennsylvanian and Mississippian throughout Colorado, Wyoming, northern Arizona and all of Utah, with variable amounts of the Mississippian strata present in the different sec- tions, may explain the absence of the Upper Mississippian strata in Blackwelder’s northern sections. That this was a long period of erosion has already been explained, and the disappearance of the Weber north- ward may well be by natural thinning due to overlap. The position of the Weber quartzite in the Oquirrh Mountains above the intercalated beds, which are not represented in the Wasatch sections and those farther to the east, indicates that the hiatus at the base of the Morgan formation in Weber Canyon represents a considerable interval of time. The Mor- gan formation is considered to be of very local extent and may be taken to be a part of the Weber. The relation of the Weber to the overlying Park City formation is de- scribed in the early reports as one of complete conformity. In the Big Cottonwood section, the division line is covered in most places and was not studied in detail by the writer. The section given by Boutwell** in the report on the Park City district, as the type section for that area, was measured in Big Cottonwood Canyon, on the ridge east of Mule Hollow. This section was verified by the writer and may be taken as representative for the upper divisions of the Weber quartzite and higher formations. Of the contact in question, the Park City report reads as follows: “No unconformity was observed with the underlying Weber quartzite, or the overlying shale, or within the formation (Park City). Accordingly, it would seem that sedimentation proceeded unbroken from Mississippian time through that part of Pennsylvanian which is represented by the Park City formation.” Blackwelder®? on the other hand concludes from his studies in Weber Canyon that there is an unconformity. He says: “The Weber quartzite is limited above by an irregular eroded surface, which is not exactly parallel to the bedding; it was subject to disintegration ; and not merely one, but a variety of beds in the formation were exposed, as is shown by the large amount of chert as well as quartzite in the breccia. On the whole, the evidence for the existence of an unconformity at this horizon seems to be conclusive. “The importance of the unconformity is uncertain. If the Weber quartzite is a formation of only local extent, and if some of the more calcareous beds farther north were deposited contemporaneously, then the observed uncon- formity may in fact be due to a slight erosion of the surface of the formation 2 Op. cit., p. 51. 32 Op. cit., p. 533. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 123 and should represent but a brief land interval. If, however, the Weber quart- zite was once far more extensive than now, and if it has been removed from the northern part of the Wasatch region, and elsewhere reduced to a varying thickness by erosion within the Pennsylvanian period, then the interval must have been relatively long. It is significant in this connection, that the frag- ments of quartzite in the basal breccia were quartzite, rather than sandstone, when broken from the parent ledge, during the erosion interval, as is shown by the preservation of sharp corners and edges.” The exact amount of time represented, if we grant the presence of an unconformity between the Weber quartzite and the Park City formation, can only be decided by finding out the ages of these two members. If the Park City formation is Pennsylvanian in age and the Weber quartzite is late Pennsylvanian, as the Oquirrh mountain sections indicate, then the interval must be short and relatively unimportant and cannot explain the great variation in thickness of the Weber and its total disappearance in sections not far distant from its type locality. If, on the other hand, the Park City formation is made Permian in age and the Weber quartzite early Pennsylvanian, then a great hiatus must exist between the two for- mations. Such a one should be well marked, and we should expect it to be especially easy to recognize where the Weber is thinnest by its most extensive erosion. The presence of a basal conglomerate with well- rounded quartzite pebbles should be expected within short distances of the present occurrences of the parent body. Again, if the Park City, formation is Permian in age and the Weber late Pennsylvanian, a small hiatus may exist between the two, such as has been described by Black- welder. It may be safely assumed that the Park City beds are late Penn- sylvanian or early Permian, and in view of the high position of the Weber quartzite in the Oquirrh mountain sections, it seems clear that no great erosion interval exists between these two formations. The thinning of the Weber is more easily accounted for by overlap, as it was undoubtedly laid down on a surface that had been long exposed to erosion. PARK CITY AND LATER FORMATIONS The Park City formation has been named from the Park City mining district within which it carries bonanza ore bodies. No good exposures are known, however, from the Park City area; and within the area specially studied for this report, the formation does not occur. It is of interest, nevertheless, to give the characters of this formation some con- sideration from the widespread occurrence of this member in the central Wasatch and northward. 124 ANNALS NEW YORK ACADEMY OF SCIENCES The Park City formation hes between the Weber quartzite and the red beds of the Woodside shale, and, in the type locality on the north side of Big Cottonwood Canyon, it has a thickness of about 600 feet. As exposed there, it consists largely of limestone with intercalations of sandstone and quartzite. Its differentiation below from the Weber quartz- ite is readily made by the appearance of calcareous layers which soon give way to a thick bed of limestone. As before stated, in the central Wa- satch this transition indicates continuous deposition from Weber into Park City time. The occurrence of limestones nearly as extensive as those of the Park City formation within the typical Weber is well known, and this suggests that the Park City beds mark the recurrence of one of these periods of limestone formation when typical marine conditions prevailed. In the older reports, the upper coal measure limestones represent this horizon. They were especially noted for the abundant fauna which they carry and have usually been regarded as of Carboniferous age. Of late, however, some tendency is shown to place them higher in the series, possibly in the Permian. In the correlation table here given, the inter- pretation of the various workers is placed at the right and that of the writer on the left. This view is supported by the fauna and stratigraphic relations which are better shown in Dry Canyon, to the north, than in Big Cottonwood Canyon. There is in that section between 500 and 600 feet of red shales and brownish sandstones between the Meekoceras beds of the Lower Triassic and the upper fossiliferous portion of the Park City formation. These seem to rest with low angular unconformity upon the Park City beds and carry an abundance of a single species of Lingula in the beds next to the contact. Faulting is frequent in this area, and the apparent discrepancy in dip between the two sets of beds may be due to that cause, but a search failed to reveal evidence of faulting. From the nature of the beds of red shale and brownish sandstones, it might be expected that they should bear a relation of unconformity, or at least disconformity, to the typical marine beds upon which they rest. From the widespread occurrence of Permian red beds in the west, these are thought to be of that age. The fauna of the upper part of the Park City formation indicates their Carboniferous age. Prominent forms are: Productus multistriatus Productus subcostatus Spiriferina pulchra Spirifer cameratus Lingaulodiscina utahensis Athyris (Seminula) argentea (Rhynchonella) Pugnar swallowiana HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 125 In Red Butte Canyon, the next gulch to the south of Dry Canyon, occurs a heavy conglomerate and a considerable, thickness of purple sandstone. These purple beds were called Permian by the geologists of the Fortieth Parallel Survey. Overlying them are the strongly cross- bedded red sandstones which form the prominent red cliff at the mouth of the canyon, from which it has derived its name. These are the “Triassic red beds” of Hague and Emmons. The discovery of the Meekoceras fauna several hundred feet below the purple sandstones has carried the lower limit of the Triassic down below what was called Per- mian into those beds which were mapped as upper coal measures by the Fortieth Parallel geologists. The simple synclinal structure for this region shown on the Great Basin sheet of that survey is now also known to be more complicated, including at least one large anticline and an- other syncline to the south of Emigration Canyon. The new geologic map of this region now being prepared by Mr. N. C. Christensen and Dr. F. J. Pack will look very different from the present one, and it is expected that the separation of the Jurassic, Triassic, Permian and Car- boniferous can be definitely accomplished in this region. For the pres- ent, the interpretation here given (page 126) is thought to be very near the true one. | MY OF SCIENCES 7 4 ANNALS NEW YORK ACADE 126 ee —_v_)]) See —= {SIYOS puvB SSIOUS UBOYOIV qStyos puv ssraur) qSIYOS puv sstousyy uBeyo1y OLAS} UN TT SOLOS o]VYS IvIU *So]BYS PUB sSopIZJABN?) | PUB 9}IZJAVNb poomMuUo}00 Sig UBIYUOST YW oyIZjlenh wvysiug aleys puw o}izqaen?) JOMO'T (Solas POOMU0}}0D SIq ) UOIJVULLOJ UOISSULTT sopizjivub puw sayejs [eip¢ounasg UOTIVULLOF 99.) a[BYS BTV UOTJVULIOZ YI WUS YOR aPPUN UBLAGWUBD UOTIBULLOF UOJSUTTIOO| (1uasqe ) uoTJeUAO; UBUNON UOIJVULLOZ SopPABYO “IS (quasqe ) jadd gq, QUOISOULT] JOpfexog | (SeyVys puv sauoysourt] snose UOIYVULLOJ BAVU!) | -JI[ISSOJUN) UOIBUUAIO; PjoyXvyy ead od (PoPVULMI]S GUOSOUM] 8} /) PUB 931 - guoysauity astpeang uasqu ; uBinoyt -7,4e0b UapsEQ) sUOJSaUTTT YoUWSE AY : pe Ee = ee ees 9UOJSOULIT UOSUBTO * euoJsoull] UOSUA UBIUOADG : PUOJSOUII] UOSIPLRIV UOT}VULIOZ Opvayy uviddississtfl o}IzjAvNb LaQqQo A UOIJVULLOJ UBIO] (quesqv ) O}IZJAVNH 19qQa A\ eyizqavnb 19qQa A\ UBLUBA|[ASUUOg dUO}SOUI] BINSBETY [VOD zodd QV UOTwULLOF APIO Ylvq UOIVULIOF APIO Fav (quesqr ) @[VYS VpIspoo AA UBIWIIO speg pez oIssBiy, (quasqe ) TO eee DISSBILT, ajBys yowyuy oIssvan (quesqe ) QUOISPULS JOoSNN oIssBun ¢ H00[BM pue (avd yyOF) SUOMI puB onsey] | JopjomyYov[g ‘e_pury ‘syoo Ay asuvy YO}ESE AL Youese A, UIOYWON YOpese AA [BIZUID poled GIAVL NOILVIGYYOO FAILLVINGL HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 19/7 nd STRUCTURE INTRODUCTORY STATEMENT The first unified account of the larger structural features of the Wasatch Mountains is that given by the geologists of the Fortieth Paral- lel Survey.** In a broad way, these early observations have been verified by the more recent studies of particular parts of the range, but many important new facts have been added and some of the original concep- tions greatly changed. Vital to the first conception of Wasatch structure was the supposed presence of an Archean axis which had the same trend as the present range, north and south, on the flanks of which were deposited the early Paleozoic sediments, until they completely buried the lofty Archean peaks. At the close of Mesozoic time, profound plicating and plateau forming movements threw the thick conformable Paleozoic and Mesozoic sediments into great pitching anticlinal and synclinal folds with axes mainly north and south. After a period of erosion during which the upper parts of the folds were planed off, profound faulting along the present western faces of the range took place, tilting the old surface eastward on the uplifted eastern side. Upon that uplifted block, erosion has carved the present relief. It is now known that the main body of supposed Archean, the Little Cottonwood granite, is intrusive, and the original conception of a pre- Cambrian protaxis has been entirely discarded. Folding is known to be much more intense than originally thought, and large overthrusts have been discovered from Ogden northward to Willard and in the Cotton- wood district. Since the overthrusting, there has been considerable deformation and faulting which have introduced the most complicated tectonic relation- ships. STRUCTURE OF THE CENTRAL WASATCH The central Wasatch is an exception, structurally, from the general anticlinal aspect of the range as a whole. Within this area, extensive intrusion of granite and granodiorite and widespread extrusion of ande- sitic lava, with their accompanying phenomena of metamorphism, are grandly displayed. Encircling the main intrusive body, the Little Cot- -tonwood granite, are steeply inclined quartzites, shales and limestones, with varying age ranging from pre-Cambrian to late Mesozoic. ‘Dipping 3. S. Geol. Expl. 40th Par., Vol. II, Sect. 3 & 4. 128 ANNALS NEW YORK ACADEMY OF SCIENCES quaquaversally from the nucleus of granite, this great series of sediments: forms the eastern half of a huge dome abruptly cut off on the west by a profound fault. The western half was depressed and is now entirely covered by the deep accumulation of rock waste forming the floor of the Salt Lake Valley. Eastward, the Carboniferous and Triassic formations are breached by an irregular stock of fine-grained granodiorite which culminates in Clayton Peak. Beyond this line of elevation, which forms the present divide, an extensive flow of andesite was poured out in an elongated synclinal depression that separates the Wasatch from the western Uintas. It is significant that the anticlinal fold of the Uinta range is in line with the eastward prolongation of this domed arch and that they are connected beneath the igneous covering by the Kamas prairie syncline. Iittle Cottonwood Granite The structural relation of the Little Cottonwood granite to the sedi- ments which flank it upon all sides has been variously interpreted. By the geologists of the Fortieth Parallel, the contact was described as one of sedimentary unconformity; and the granite was thought to be older than the quartzites that appear to overlap it. The absence of a basal conglomerate was noted, and the whole situation was thought to be ex- traordinary. At that time, the intrusive occurrence of granite had not been conceived, and the indications of contact and regional metamorphism escaped notice, so that while the evidence of a sedimentary contact was not in accord with conditions commonly regarded as necessary, the rela- tion was still held to be due to sedimentation. In 1880, Geikie** visited this region and later published his conclu- sions. He found structural evidence that led him to regard the granite as intrusive, and probably post-Carboniferous in age, rather than pre- Cambrian as given by the Fortieth Parallel geologists. In 1900, Boutwell visited Little Cottonwood Canyon and examined the contact of the granite and quartzite on the ridge south of Twin Peaks. Here he found dikes of granite extending up into the quartzite and sills of granite leading off laterally from the dikes. Inclusions of quartzite in the granite were also observed, and the intrusive nature of the granite was thus established. These results were verified by Em- mons**® who later published his conclusions regarding the granite as in- 3% A. Gpikien: “Archean Rocks of Wasatch Mountains,’ Am. Jour. Sci., 3rd Ser., Vol. 19, pp. 363-367. 1880. 3S. F. Emmons: “Little Cottonwood Granite Body of the Wasatch Mountains,” Am. Jour. Sci., 4th Ser., Vol. 16, pp. 1389-147. 1903. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 129 trusive and pre-Jurassic in age and the chief folding of the sediments as Jurassic. The Little Cottonwood granite has commonly been regarded as lac- colithic in structure, since its intrusive character has been known. While the inclosing quartzites do dip away in all directions from the central igneous mass, suggesting that they may have been arched up by the in- trusion, the essentials of laccolithic structure are nowhere shown. ‘The far-reaching metamorphic effects of the granite upon the contiguous sediments, its uneven ragged contact on all sides and its thorough crys- talline coarse texture all indicate a mass of irregular shape and great size. It would seem advisable, therefore, to speak of the Little Cotton- wood mass as a stock and reserve the term laccolith for the more special type of intrusive. As to the geologic data of the intrusion, there is also much uncertainty. The latest sediments cut are Algonkian, and possibly Lower Huronian, in age. If the mass were known to be laccolithic, then the latest sedi- ments affected by the arching would give the desired information; or, if the doming of the strata is due to the intrusion of the granitic stock, then the age might quite easily be stated as later than the youngest beds that are involved. But it is difficult in this region of strong folding to distinguish between the flexing due to regional folding and that due to a special cause such as intrusion, where the two come so close together. A few general considerations may lead to a closer approximation of the date of the intrusion than can be made from the sediments cut by it. The Little Cottonwood granite mass les in an east-west zone of eruption which has been active in some parts in post-Triassic, probably Tertiary time. At Bingham, it is marked by a large body of post-Carboniferous monzonite and trachytic extrusion. Still farther west, the sheets and dikes of the Mercur and Ophir districts are in the westward continuation of this belt. Just east of Alta is a large irregular stock of granodiorite which cuts Carboniferous limestones and adjoining it to the east is the Clayton Peak mass of quartz diorite which cuts Triassic strata. The interrelations of these three main intrusive bodies have not been discovy- ered in the field. They are not in surface connection with each other, so far as known, but a northeast-southwest system of dikes and veins is characteristic of the whole region; and closely associated with the ore bodies. These dikes are clearly later than the folding, since they do not show deformation and from their similarity to the larger intrusive masses they may be assumed to have come from them, though none has actually been traced to the junction point. They are seen to disappear beneath rock debris within a few hundred feet of the larger bodies, however, and 130 ANNALS NEW YORK ACADEMY OF SCIENCES are surely connected with them. If such a contact could be seen, it would shed much light upon the relative ages, but in the absence of actual proof, we may only reason about them. If we assume that the Little Cottonwood granite, the Alta granodiorite and the Clayton Peak quartz diorite are connected below, as is commonly done, they are probably not of very different ages and may be taken as being as young as the most recent sediments cut. This would make them post-Triassic. If the fracturing of the beds and intrusion of the dikes came after the folding, which is thought to be late Cretaceous, and if this occurred contemporaneously with the intrusion of the larger bodies, as might be the case, then the Little Cottonwood granite, as well as most of the other igneous masses, are post-Cretaceous. The extrusive andesites of the Kamas prairie to the east are in contact with the Vermillion Creek beds of the Eocene as reported by the Fortieth Parallel geologists.*° They are thus later than these early Eocene beds and represent the latest igneous activity of the region. Their relation to the porphyritic dikes and granitoid intrusives of the Cottonwoods is not known, but they are probably much later. The Little Cottonwood granite was no doubt uncovered during the period of erosion which followed the post-Cretaceous folding. The extrusions came after the upturned Paleo- zoic and Mesozoic beds had been strongly truncated, covering the old surface in the depression between the Wasatch and Uinta mountains, The date of the intrusion of the granite will presently be further dis- cussed when the problem of overthrusting and faulting near Alta is taken up. From the above, it appears that the granite probably came in 1mme- diately preceding or possibly accompanying the folding in post-Cretaceous time. The eruptive andesites are post-Vermillion Creek and belong un- doubtedly to the Tertiary period. STRUCTURE NEAR ALTA In the Alta region, the most obvious structure is an eastward dipping monocline, which to the north and south slowly curves westward, in ac- cordance with the general dome structure for this part of the range. The strata stand at a considerable inclination, averaging between 35 and 45 degrees, but locally the dip may be much more and in some parts notably less. This simple structure is much complicated in places by folding and faulting. The folds are confined to a zone within the sedi- mentary series, the formations above and below having the ordinary monoclinal attitude. This condition has been brought about by over- %*S. Ff. EMMONS: U. S. Geol. Expl. 40th Par., Vol. I, pp. 586-587. 1878. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 131 thrusting, the weaker members in the lower part of the overthrust mass having been rolled together in such a way as to make it almost hopeless to try to make out any regular structures. Small Z-shaped folds have resulted in several places, and in others, overturned and isoclinal folding may be observed. North and south of Alta where the disturbance seems to have been the greatest, the weak shales of the Cambrian system have been drawn out into long tongues in the midst of the quartzites, entirely isolated from the limestones which normally overlie them. The dynamics by which this was accomplished in a region so complicated can hardly be explained. The strata plainly show that they have been torn loose from their normal position in the sedimentary series and involved in the zone of shearing so as to be widely separated from their former position. In Big Cottonwood Canyon, above the Alta black shale exposed near the old Maxfield mine, rises a great series of limestones. Below the shale is a thickness of about 1200 to 1500 feet of Cambrian quartzite, and below that the Algonkian quartzite slate series 11,000 feet thick forms the base of the section. There is thus in Big Cottonwood Canyon a great limestone series overlying the Alta shale. These may both be traced south- east across the canyon where the limestones are seen to form the top of Kessler’s Peak. Still farther along the strike, they cross South Fork and are best seen as the chief rocks making up the Reade and Benson ridge, on the east wall of South Fork. They may be continuously followed south into Little Cottonwood Canyon where they form the ore-bearing zone north of Alta. The Cambrian black shale can be traced along in the same way and some of the underlying quartzite, but just below Alta a second lower series of limestones outcrops in bold cliffs on both sides of the canyon, facing Superior and Peruvian gulches. To one familiar with the Big Cottonwood succession where no limestones appear below the Cambrian rocks, this condition at once suggests an overthrust. An ex- amination of the rocks below the lower limestone revealed the Cambrian black shale as the first member and the familiar Lower Cambrian quartz- ites and the upper part of the Algonkian quartzite and slate series as the downward continuous succession. Below the upper limestones, which were traced over from Big Cottonwood, are, in order going down, the Cambrian black shale (Alta), the Lower Cambrian quartzite (Brigham) and the upper part of the Algonkian series which rests upon the lower limestones. There is thus a complete duplication of the strata from the upper part of the Algonkian through the Cambrian and including the lower 1000 feet of limestone of Ordovician and Devonian age. The evi- dence for overthrusting is therefore conclusive from a stratigraphic view- point. It seems strange that the Fortieth Parallel geologists should 132 ANNALS NEW YORK ACADEMY OF SCIENCES have overlooked this relationship. They seem to have been prejudiced from the similar relations which they had observed in the range to the north, in Weber and Ogden Canyons. In describing the Big Cottonwood section, King*’ has the following to say: “Next above the Cambrian lie 1,000 feet of Ute limestone, which for the most part is very light colored, highly crystalline and characterized by peculiar cloudings of color that extend across the beds near the bottom of the series, and at one or two horizons near the top it is noticeable for containing a large proportion of tremolite, and under the microscope it is seen to be highly siliceous, the silica appearing as rounded glass grains of pellucid quartz. The outcrop extends up the hills on both sides of the canyon and to the south is conspicuous upon the divide, from which it descends into Little Cottonwood and in the valley a little way below .Alta exposes a fine precipitous cliff, the result of a fault (the Superior fault of this report). Here again are seen the same highly crystalline, almost marble-like condition and the same prevalence of tremolite and silica. Under these circumstances it is not at all remarkable that the beds contain no fossils, but it is unquestionably Silurian. as will be seen later. “Above the limestone occurs the white granular body of Ogden quartzite, which is here reduced in thickness to about 800 feet. It may be traced up the hill to the south and forms an interesting saddle in the ridge top, between the Ute limestone and the bold masses of Wasatch limestone which directly overlie it. Here are but limited traces of the thin body of greenish argillites that far- ther south, in the region of Rock Creek, were found on both sides as bounding- beds to the Ogden body.” The presence of the “Ogden” quartzite between the “Ute” and “Wa- satch” limestones in the Big Cottonwood section seems to have been inferred from its prominent appearance on the ridge above Alta. In Big Cottonwood Canyon, no such quartzite member is exposed. The outcrop at the head of South Fork, having the described position between the two limestone members, can be traced northward along the strike of the beds into Big Cottonwood Canyon, where it appears below the lowest lime- stones there exposed. It therefore clearly belongs to the Cambrian. This fact might easily have been discovered had the early geologists attempted to explain the presence of a black shale above the “Ogden” quartzite on the ridge above Alta. For some reason this important horizon marker was overlooked or disregarded altogether. The “limited traces” above referred to are hard to harmonize with the good exposure of this Cam- brian shale at the south end of the Reade and Benson ridge, where it shows its typical thickness, between 150 and 200 feet. The lower occur- rence, below the “Ute” limestone, seems to have been noted, though the 7 C, Kine: U. S. Geol. Expl. 40th Par., Vol. I, Sys. Geol., pp. 167-168. 1878. * HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 138 thickness and exposure there are hardly more favorable for observation. The strong contrast between the black shale and the almost white quartzite makes the presence of the shale easy to recognize and renders it one of the best guides to the surface geology of the region (see Plate III, A). Alta Overthrust As already stated above, there is complete stratigraphic evidence of a large overthrust in the vicinity of Alta, for which the name Alta over- thrust is proposed. It has been traced north from the locality where it was first discovered northwest of Alta into Big Cottonwood Canyon and south into American Fork. There can be little doubt, however, that it extends much farther in both directions. The dip of the overthrust beds is not very different from that of the strata upon which they rest, so that the attitude of the beds above the thrust surface furnished no clue to the relationship. The strong contrast in color and lithologic characters be- tween the various stratigraphic members soon led to the recognition of a complete duplication of beds. The other factors were then soon discov- ered. Evidence of intense dynamic action was found in the highly folded and contorted conditions of the weaker strata. Rapid variation in the thickness of the beds, and the complete disappearance of some of them above and below the thrust surface were noted. The accompanying diagram (Fig. 5) shows the relation of the beds above and below the thrust surface as they occur between Alta and Argenta, a distance of about four miles. The succession at the right is the same as that seen in the photograph (Plate IV, A). As we go north- west, the lower members of the series above the thrust line T T’, as well as the limestones and shale below it, disappear, so that when Argenta is reached these beds are missing. The Cambrian quartzite has apparently become much thicker, being nearly twice as thick as it is in the two ex- posures near Alta and at the head of South Fork. The only duplication of strata shown in Big Cottonwood is the Cambrian quartzite, and that shows itself in the increased thickness of the beds, the exact line of sepa- ration not having been observed. On the north slopes of Kessler’s Peak coming around from Mineral Fork, the thrust surface disappears beneath a heavy mantle of débris, and where it emerges on the north slopes of Big Cottonwood, it has not been found again. From Alta southward, the thrust surface is more easily traced. The lower limestones outcrop all along the east wall of Peruvian Gulch to the Bullion Divide, where they cross over in a low saddle and form the floor of the great cirque at the head of American Fork, known as Min- 134 ANNALS NEW YORK ACADEMY OF SCIENCES e eral Flat. The lowest overthrust member is quartzite, plainly seen as the capping of Bald Mountain directly south of Alta (see geologic map, Plate VI). All along Peruvian Gulch and in American Fork, this seems to lie conformably upon the limestone. Both the limestone and the quartzite being very resistant, the contact is often sharp with very little crumpling or brecciation. ‘The truncation of the beds, however, shows beyond any doubt the secondary nature of the structure. More- Argenta Alta FIG. 5. SECTION BETWEEN ARGENTA, IN BIG COTTONWOOD CANYON, AND ALTA, IN LITTLE COTTONWOOD Relation of the overthrust Paleozoic and Proterozoic strata to beds of the same ages below 1 — Algonkian quartzite. 2— Algonkian ‘‘conglomerate.” 38=——=Cambrian quartzite 4—Cambrian shale. 5— Ordovician and Devonian limestones. TT’ — Thrust surface over, in many places crumpling and brecciation have occurred—as should be expected. In all such cases, the limestones have been the least af- fected, but the overthrust quartzites and shales have suffered strong deformation. The best example of this condition is seen on the slopes northwest of Alta. The black Cambrian shale has here been drawn out into a long tongue in the midst of the quartzite, showing every inclination from strongly overturned folds near the Columbus mine to a vertical posi- tion farther up the hill. The quartzite is folded and smashed in such a way as to’ be chaotic, individual blocks being traceable for short distances only. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 135 In the mine workings on this hill, the discontinuity of the beds seen on the surface is also shown. No regular structure can be followed very far within the quartzite, or overthrust zone. The deeper workings which drift far to the westward finally enter the limestones below the thrust mass, and here the dip is regular to the east. The thrust contact dips strongly to the east on the surface, but deeper it gradually flattens out. The age of the overthrust is not positively known, but there can be little doubt that it occurred during, or at least at the close of one of the periods of folding in late Mesozoic time. The folding of the Wasatch is generally assigned to the close of the Cretaceous, but King** has de- scribed an unconformable contact between the local Dakota beds and the Jurassic and older sediments exposed along Mountain Dell road in the upper part of Parley’s Canyon. The difference in dip of the beds is given as about 30 degrees, and the Cretaceous strata rest on the truncated edges of all of the older Mesozoic and Paleozoic formations, but else- where the Cretaceous is described as conformable with the older series, and this relation is the commonly accepted one. More work will have to be done to settle this question. If there was important folding at the close of the Jurassic, the overthrust in the Cottonwood region could have occurred then. It certainly took place before the intrusive action oc- curred in this district, as is evidenced by the independent manner in which the dikes cut through the basal series and overthrust blocks. This event followed or accompanied a period of northeast-southwest fracturing and faulting which preceded the period of mineralization. Still later, important faulting transverse to this first fracture line occurred, of which the Superior fault is the best known example. The overthrusting, there- fore, appears to have happened along with or following the first dynamic disturbance in the region. Later warping has deformed the thrust sur- face and tilted the masses at a high angle. Farther north in the range, Blackwelder*®® has described similar struc- tures which he thinks were made at the same time that the Paleozoic rocks were folded, which is generally assigned to the close of the Cre- taceous period, but he says “It seems to be a fact that the Lower Eocene (Wasatch) sediments cover the outcrop of the overthrusts in several places, thus indicating that the folded and overthrust structures had been deeply eroded.” It is quite likely that these two districts less than fifty miles apart suffered overthrusting at the same time and that whatever period is deduced for one will be found to be the same for the other. %C, Kina: U. S. Geol. Expl. 40th Par., Vol. I, p. 304. % EK. BLACKWELDER: ‘‘New Light on the Geology of Wasatch Mountains,” Bull. G. 8. AGy Vole v2). Derooo- 136 ANNALS NEW YORK ACADEMY OF SCIENCES From southeastern Idaho and northern Utah, Richards and Mansfield*® have described a great overthrust which involves strata of late Cretaceous age. The oldest rocks which have been found concealing its trace are the early Eocene conglomerate of the Almy formation,*? making the possible range of age from late Cretaceous to early Kocene. ‘This agrees closely with Blackwelder’s determination for the Willard overthrust near Ogden, Utah. The latest beds involved in the Alta overthrust are Pennsylvanian within the area studied, but from the general fact that overthrusting accompanies or follows strong folding, the overthrusts of the central Wasatch must belong to the late Mesozoic and are probably of the same age as the great Willard and Bannock thrusts. The trace of the Alta overthrust has a trend north-northwest, while the thrust surface dips strongly to the east with the general monoclinal structure of the region. ‘This leads to the belief that the movement was from east to west, though this is only tentative. The overthrust block seems to be continuous for eight or ten miles to the east, where it disap- pears below the quaternary beds of Kamas and Weber valleys. More extended work will be needed, however, to show definitely that the direc- tion of thrusting is as above indicated. Blackwelder thinks the overthrusting near Ogden came from the east, but Richards and Mansfield have questioned the correctness of this de- termination, as they believe it came from the west. There is thus a difference of opinion in a region perhaps better adapted to the determina- tion of this question. It might be said, however, that the unsymmetrical anticlines of the Cottonwood region are steepest on the west, and in one or two cases seem to be overturned in that direction, suggesting strong lateral pressure from the east. The structural relations along the trace of the Alta overthrust are shown in the structure sections accompanying the geologic map. A Minor Overthrust Immediately south of the town of Alta there is a mass of limestone, shale and quartzite which stands nearly vertical, dipping slightly to the west. In Collins’s Gulch, the strata dip eastward at an angle of about 25 degrees. Across the ridge to the east of the Albion tunnel, the quartzites appear again with an eastern dip. There is thus between Collins’s Gulch and the great cirque south of Alta, a mass of limestone, shale and quartzite , ©R. W. RicHarps and G. R. MANSFIELD: ‘‘The Bannock Overthrust,’’ Jour. of Geol., Vol: (20; No: 8: 1912: “U.S. Geol. Surv. Prof. Paper No. 56, p. 89. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 137 which is overturned and does not match with the lower beds on either side. All attempts to explain the structure as a syncline, or overturned anticline, fail when the succession of beds is noted, leaving the only rea- sonable basis of explanation that of an overthrust block. Faults In a region of such complicated structure, faulting may be expected to occur. Dislocations are met with in every mine, but those on a big scale are few in number. Whether large or small, they appear to belong to two systems of fracturing, but movement has probably occurred more than once in each system. The directions of these two sets of fractures are respectively north-east and south-west for those carrying the ores and dikes, and northwest-southeast. These correspond to the dip and strike of the Alta monocline and may therefore be classified as dip faults and strike faults. The earliest displacements are those in which the fissure veins carrying the ore were found. ‘These have a fairly constant direction, N. 70° E., and no doubt belong to the same period of fracturing which gave rise to the lode deposits of the Park City district which he in the path of their northeastward extension. Into some of these, the dikes which are com- mon in the southern part of the district were injected, and it is thought that the ore-bearing solutions came up in others at the same time, or immediately following, depositing the ores. The displacements above this first set of fractures do not appear to have been very great. They are probably more in the nature of great cracks which were formed through the effects of intrusion of the larger bodies of igneous rock to the east and west, as inferred from the correspondence of their direction with the general trend of the intrusives. On the other hand, when com- ‘pared with the general dome structure of the region they are radial and might be considered as tension cracks made when the region was thrown into its present arched condition. After the formation of the ore deposits of the district in the northeast- southwest fissures, a second period of faulting occurred, having a trans- verse direction to the first set of fractures. This is shown in the north- west-southeast faults encountered in many of the mines, where they in- variably displace the ore bodies. A notable case is the great Atwood “slip” which cut out the ore of the famous Emma mine. Many other examples are known in the various mining properties. The displacements of these strike faults are much greater than those of the earlier fractures. The one occurring in Superior Gulch running north into South Fork appears to have the greatest throw and has been 138 ANNALS NEW YORK ACADEMY OF SCIENCES called the Superior fault. A second one of great size cuts across the ridge from the head of Silver Fork into the Alta basin. It is seen most clearly on the ridge northeast of the Emma mine, where the fault breccia. has weathered into relief, standing up like a great wall. This fault will be described as the Silver Fork fault. In all of these movements, the displacements are more in the vertical direction, WE shifting’ being not so frequently met with. Superior fault——The Superior fault as shown upon the map (Plate VI) can be traced from the mouth of Superior Gulch in Little Cotton- wood Canyon northward into South Fork. On the top of the ridge, it. is clearly marked by a wall of breccia which stands up ten feet above the general level of the surface. The crushed zone marked by the breccia may be followed northward for nearly a mile. In the upper tunnel of the Cardiff mine, it is well shown for a distance of a thousand feet along which the hanging wall is quartzite and the foot wall very hard limestone. From all indications in South Fork, where it was first encountered, it may be explained as a normal fault with a throw of about a thousand feet, but observations from the Alta side of the divide clearly show it to be a reverse fault of less magnitude, the displacement being about 600 feet. The limestones on the west are lifted. They belong to the lower series exposed on the east wall of Superior Gulch and not to the lime- stones of the Reade and Benson ridge as at first supposed. This was not. understood until the overthrusting which duplicated part of the series. was discovered at Alta. The limestones are all of the same age but they occur in two series separated by nearly a thousand feet of older quartzite belonging to the overthrust member. The faulting is clearly of later date than the overthrusting. The understanding of this relationship is of the utmost importance to the mining people of South Fork, who have never suspected the presence of a limestone series below the quartzites of the. Reade and Benson ridge. The cherty limestones forming the ridge south of the Cardiff office and boarding house are the lifted, westward extension of that lower series upon which the overthrust block rests. The relation is clearly brought out in Section A-A, Plate VI (see also Plate III). The direction of this movement is more nearly vertical than horizontal though the oblique flutings on the walls in the Cardiff tunnel indicate an important horizontal component toward the north on the west side. Surface evidence of faulting cannot be traced farther than the Cardiff mine to the northward, though it is safe to assume that a movement so pronounced at this last observation point must have continued for some distance beyond. At a point about a mile and a quarter north of the Cardiff, the bottom of South Fork is composed of limestone, and no HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 139 evidence of faulting could be found; but on the north wall of Big Cot- tonwood Canyon opposite South Fork, faulting is clearly shown, Here the west block has gone down instead of up. If this fault has anything to do with the Superior fault, it must be in the nature of a pivotal fault with the fulerum somewhere between the Cardiff mine and the mouth of South Fork. Silver Fork fault—At the head of Silver Fork of Big Cottonwood Canyon, ‘on the ridge north of Alta, there is a wall of limestone breccia which stands up from 10 to 20 feet above the crest of the ridge, having a direction nearly north and south. On both sides of it are limestones, but their metamorphic condition prevents close observation as to the strati- graphic displacement because of the difficulty of identifying a suitable datum plane on both sides. Farther to the south in the gulch leading from Alta to the City Rocks and Alta Consolidated mines, the quartzite and shale of Cambrian age are faulted up on the east so that they are in contact with the limestones which normally overlie them. The displace- ment is estimated to be between 500 and 600 feet, though the exact amount of movement could not be readily determined. It is, however, a fault of considerable magnitude. The fault surface seems to be vertical, and it is therefore impossible to say whether it is of the normal or the reversed type. Minor parallel faults may easily be detected to the west along the top of Emma Hill and Flagstaff Mountain, but on account of the strongly metamorphosed condition of the limestones, the throws have not been determined. They are, however, thought to be only slight. It might be said by way of generalization that the block between the Su- perior and Silver Fork faults has gone down and that the west end ap- pears to have been most depressed. The parallel fractures between them, therefore, may show that the west side has gone down in most cases. This, however, is merely a suggestion and may not be true in all cases. Minor faults—In the various mines of Alta, minor faults are known to be of frequent occurrence. They conform generally to the main direc- tions of fracturing already referred to as northeast-southwest and south- east-northwest. The latter are invariably found to be younger than the northeast-southwest series of faults. The Columbus Extension tunnel has been driven northwest for a considerable distance along one of these breaks. Near the mouth of the tunnel, a displacement of 90 feet has been observed, but farther to the north it is probably less. On.the divide between South Fork and Alta, a fault with a throw of about 30 feet is clearly shown on the surface. The west side has been depressed. This fault is shown in the structure sections B-B* and C—C on the map. 140 ANNALS NEW YORK ACADEMY OF SCIENCES South of the Columbus Extension, in the Alta Hecla property, several of these north-south vertical faults are to be seen underground. Pros- pecting along them has failed to develop ore except where the northeast- southwest fissures have been crossed. In every case, these ore-bearing fissures are offset, showing them to be older. The amount of shifting has only been worked out in the one case above cited, as far as known, but generally the displacements are not very great, except in the two large faults already described. SUMMARY OF CONCLUSIONS PHYSIOGRAPHY (a) The central Wasatch is a maturely dissected block mountain, pre- serving in a modified condition the form of its original profile. (6) Before the Wasatch fault was formed, the folded Wasatch forma- tions were planed off by erosion, and several plutonic igneous masses were uncovered, notably the Little Cottonwood granite, the Alta grano- diorite and the Clayton Peak quartz diorite stocks. (c) Block-faulting in Tertiary time gave rise to the Great Basin ranges, and at the same time the Wasatch block was uplifted. When newly formed, it had a steep western face and a long gentle eastern back slope. (d) The original crest line was the upper edge of the great fault es- carpment on the west. This was also the original divide. (e) The divide has migrated from its first position near the western margin to its present position near the eastern margin of the block. The present long west-flowing streams of such canyons as Big and Little Cottonwood are chiefly obsequent streams, being consequent near their mouths. (f) The crest line has moved in the same direction as the divide, but only a short distance. (7) The Provo and Weber Rivers are probably also obsequent streams in their canyons across the Wasatch. ‘Their head-waters are the eastern consequents that have been captured, so far as the drainage of the Wasatch is concerned. (h) The mature dissection of the Wasatch by stream action was ac- complished before the Pleistocene. Upon the stream-cut topography certain features were superposed due to glaciation during the Pleistocene. Later modifications have been slight. . HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 141 STRATIGRAPHY (1) The major part of the great quartzite and slate series exposed in Big Cottonwood Canyon is Algonkian and possibly Lower Huronian in age. | (j) The Lower Cambrian is separated from the Algonkian by a heavy basal conglomerate of widespread occurrence. The Cambrian strata of the central Wasatch belong to the lower and middle divisions of the Cam- brian system and are less than one thousand feet thick. (k) Above the known Cambrian are about 500 feet of unfossiliferous limestones and calcareous shales provisionally referred to the Ordovician. Silurian strata are entirely wanting in the Cottonwood region. (1) Middle and Upper Devonian horizons are represented by what ap- pears to be an unbroken succession of limestones carrying faunas closely allied to those found in western Colorado and Iowa. ( m) The Devonian beds rest with disconformity upon the lower lime- stones and are separated from them by a thin bed of conglomerate com- . posed of limestone pebbles. (n) The Mississippian follows the Devonian conformably and is repre- sented by limestones of Lower and Middle Mississippian age which are separated by a continental formation. (0) In the Cottonwood region, there is an unconformity between the Mississippian and the Pennsylvanian (Weber quartzite) which follows, representing a considerable erosion interval. The thinning of the Weber quartzite is probably to be accounted for by overlap upon this erosion surface. (p) The Wasatch limestone of the Fortieth Parallel geologists em- braces strata of Ordovician, Devonian and Mississippian ages. The Ogden quartzite and Ute limestone of supposed Devonian and Silurian ages respectively have no existence, as originally defined, in the central Wasatch. STRUCTURE (q) In the vicinity of Alta there is a great overthrust, presumably from east to west; the overthrust block consists of beds ranging in age from Algonkian through the Paleozoic and Mesozoic; the underthrust member consists of Devonian and older beds. (r) The age of the overthrust is probably the same as the main fold- ings of the Wasatch, generally assigned to the end of the Cretaceous. - 142 ANNALS NEW YORK ACADEMY OF SCIENCES (s) After the overthrusting occurred, there followed a period of in- trusion in which large irregular granitic and dioritic masses together with numerous dikes were injected into the Mesozoic and older forma- tions. (t) North-south faulting near Alta has resulted in the formation of two master faults and numerous minor fractures. These run roughly parallel to the main Wasatch fault line and probably belong to the same period of readjustment. BIBLIOGRAPHY PHYSIOGRAPHY Atwoop, W. W.: Glaciation of the Uinta and Wasatch Mountains, hes U.48: Geol. Surv. Prof. Pap. No. 61. 1909. Davis, W. M.: Ranges of the Great Basin: Physiographic Evidence of Fault- ing. Sci., Vol. XIV, pp. 457-459. 1901. Emmons, S. F.: Rept. U. S. Geol. Surv. 40th Par. Descr. Geol., Vol. II. 1877. GEIKIE, A.: Ancient Glaciers of the Rocky Mountains. Am. Nat., Vol. 15, p. 3. 1881. GILBERT, G. K.: Geographical and Geological Explorations and Surveys West of the 100th Meridian, Vol. III, pp. 17-187. Washington, 1875. : Lake Bonneville. U. S. Geol. Surv. Monograph I. JOHNSON, D. W.: Block Mountains in New Mexico. Am. Geol., Vol. XXX, pp. 135-1389. 1908. KING, CLARENCE: Rept. U. S. Geol. Surv. 40th Par. Sys. Geol., Vol. I. 1878. LE ConTE, JOSEPH: Origin of Normal Faults and of the Structure of the Basin Region. Am. Jour. Sci., 3rd Ser., Vol. XX XVIII, p. 257. 1889. RUSSELL, I. C.: Geological History of Lake Lahontan. U. S. Geol. Surv. Monograph XI. 1885. Spurr, J. E.: Origin and Structure of the Basin Ranges. Bull. Geol. Soc. Am., Vol. 12, pp. 217-270. 1901. STRATIGRAPHY AND PALEONTOLOGY BERKEY, C. P.: Stratigraphy of the Uinta Mountains. Bull. Geol. Soc. Am., Vol. 16, pp. 517-530. 1905. BLACKWELDER, E.: New Light on the Geology of the Wasatch Mountains. Bull. Geol. Soc. Am., Vol. 17, pp. 517-533. 1910. : Handbuch der Regionalen Geologie, Vol. 8, Pt. 2, p. 136. Heidelberg, 1912. BouTwELL, J. M.: Geology and Ore Deposits of the Park City District, Utah. U. S. Geol. Surv., Prof. Pap. No. 77, pp. 41-65. 1912. Emmons, S. F.: Rept. U. S. Geol. Expl. 40th Par., Vol. 2, p. 342. 1877. Girty, G. H.: Carboniferous Formations and Faunas of Colorado. U. S. Geol. Surv. Prof. Pap. No. 16. 1903. HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 143 KINDLE, E. M.: Silurian Faunas of Western America. Am. Jour. Sci., Vol. 25, pp. 127-128. 1908. : Devonian Fauna of the Jefferson Limestone. Bull. Am. Pal., Vol. 4, No. 20. 1908. KING, CLARENCE: Rept. U. S. Geol. Expl. 40th Par. Sys. Geol., Vol. 1. 1878. PEALE, A. C.: U. S. Geol. Surv. of Mont., Ida., Wyo. and Utah (Hayden), pp. 105-108. 1872. TENNY, S.: Devonian Fossils in the Wasatch Mountains. Am. Jour. Sci., 3rd Ser., Vol. 5, pp. 189-140. 1873. Watcort, C. D.: Second Contribution to the Studies on the Cambrian Faunas of North America. U. S. Geol. Surv., Bull. No. 30. 1886. : Cor. Pap., Cambrian. U.S. Geol. Surv. Bull. No. 81. 1891. : Cambian Sections of the Cordilleran Area. Smith Misc. Coll., Vol. 53, No. 5. 1908. STRUCTURE BLACKWELDER, E.: New Light on the Geology of the Wasatch Mountains, Utah. Bull. Geol. Soc. Am., Vol. 17, pp. 533-542. 1910. BoutwEL., J. M.: Geology and Ore Deposits of the Park City District, Utah. U. S. Geol. Surv. Prof. Pap. No. 77, p. 48. 1912. Dana, J. D.: Rocky Mountain Protaxis and post-Cretaceous Mountain Making Along Its Course. Am. Jour. Sci., 3rd Ser., Vol. 40, p. 187. 1890. Emmons, S. F.: Rept. U. S. Geol. Expl. 40th Par., Vol. 2. 1877. : The Wasatch Mountains and the Geologic Panorama of the Wasatch Range. Comp. Rend., Int. Geol. Cong., 5th Ses. 1891. : Little Cottonwood Granite Body of the Wasatch Mountains. Am. Jour. Sci., 4th Ser., Vol. 16, pp. 189-147. 1903. GEIKIE, A.: Archean Rocks of the Wasatch Mountains. Am. Jour. Sci., 3rd Ser., Vol. 19, pp. 363-367. 1880. GILBERT, G. K.: The Wasatch, a Growing Mountain. Bull. Wash. Phil. Soc., Vol. 2, p. 195. : A Theory of Earthquakes of the Great Basin. Am. Jour. Sci., 3rd Ser., Vol. 27, pp. 49-53. 1884. Hitts, R. C.: Orographiec and Structural Features of the Rocky Mountain Geology. Proc. Col. Sci. Soc., Vol. 3, pp. 362-388, 400. 1891. Kine, CLARENCE: Rept. U. S. Geol. Expl. 40th Par. Sys. Geol., Vol. 1. 1878. RicHaRps, R. W. and MANSFIELD, G. R.: The Bannock Overthrust: A Major Fault in Southeastern Idaho and Northeastern Utah. Jour. Geol., Vol. XX, No. 8, pp. 681-709. 1912. er . ‘ ay ae My ; f rn oe on ~ om i or sa aha A: noes hi a, 0 cas ie: i Ae Hai a om ey e Gls : ? Fas | ap ‘ ite vn | Pu he vs Va ij? ts 1s My a (Air Tate Jaton ts va Pe xsi = " 7 nk ; wee ioe Cae haste cee 4 p 7 my ; i, rh 7 oe iv i ’ | ae Hy) Y ‘ : . ata ye PLATE I A. LOWER HALF OF SOUTH FORK OPPOSITE MILL D. BIG COTTONWOOD CANYON, LOOKING NORTH Shows broad U-shaped glacial trough, with terminal moraine at the junction of the main canyon B. CONGLOMERATE AT THE BASE OF THE CAMBRIAN QUARTZITE IN LITTLE COTTON- WOOD CANYON, JUST BELOW ALTA 1 WTAAD VOYMAD GOOWKOTTOO DIA .a LUM arTia0owio AXOT HTV0A TO WIA SUWOI iA HraoKw SATAOOL foitount oft ts onistoa {sainrrst iw «dguot Isiosle heqside-J bso ewode foyer coisa oct to . -WOTTOD AITITLI Vil ATINTAAUQ MAISAMAO AHT WO AAAS AHT TA ATARAMOIDHOD ATIA WOUGE TAUL WOYVAD GOOW f ~ \ I SNE VLA VOLUME Scr. ACAD. ANNALS N. Y. » eS we a ¥ <> oe . . - _ 4 A im) F . . PLATE II A. PHOTOMICROGRAPH OF “‘TILLITE’ FROM THE HEAD OF SOUTH FORK Showing rounded and angular fragments, chiefly quartz, in a dark matrix, principally biotite. Enlarged 25 diameters B. PHOTOGRAPH OF HAND SPECIMEN OF “TILLITE’” FROM SOUTH FORK Showing rounded quartzite pebble in black groundmass. Natural size aot ¥rv0a 40 dAdH aHT wom "arn ‘40 esaomonacnont . SR “ay % aiatoutb PENS boxraladt “osiotd -@a0% HTUOa Mos Carnua 10 wana ava sae & > sale leraia zombavors aopld ai 1 adda ouisvinnp _) 2 4 ANNALS N. Y. Acap. Sc1. VOLUME XXIII, Puate II PLATE III . ‘A. THE DIVIDE AT THE HEAD OF SOUTH FORK AND THE GEOLOGIC EXPOSURES OF THE SOUTH END OF THE READE AND BENSON RIDGE 4 Showing the overthrust members above the Superior fault B. NEAR VIEW OF THE UPPER CENTRAL PART OF FIG. A Showing, from left to right, the Cambrian shale, Cambrian quartzite, Algonkian “conglomerate” and quartzite ? 7 - Pe. oy Po yr . ; ‘ ve a . ' ‘ ‘ ? ‘ { ] " 7 e ri t {* ‘ ¢ : ~ - » } + 7 ’ Tas “ } *) 70 > - ma “a } $e , ‘ : , . : 4 r Baas eat tei, aor noRMat GA Ad Ade > . r ’ a } p " y sf = ; e*, ‘ 3 ae. a ‘ ae yy ANNALS N. Y. AcAD. Scr, VOLUME NXT, Pruaty Trl ee lp, 6 eee ~ » ; “Px. 2 al Po? ae Pe eee ee ee ee eee ‘> eae! nw a } : j é eid A ‘. ae Pa ee) ® ’ 7 - S, ' : > its on ee, ile oe : sy ; = Wao 4 aL : 7 Lj | Nite, {S005 hao. ne bia . ae . ” on ive fi ; a aS . : a te - i , 5 = 9 oe » \ - = ae 's _ » de e ( er : 25 et gett to Ty » 244 Peart » a ‘4 ,* re ) : : e il nay y! - @ -— &, » * 4 : h i ¢ ng = : * “ Se - ‘ i ? co > é o = e t~¢ ’ ‘ = ' ~ J + 4 2 a] , 7 « LJ ® : ‘ - * I = . . 7 it > “ , 5 ‘ aX 4 Den x - >- 7 “i 7 - a Al - -; , i 7 . : © , ‘ ,.. La te =~ . 7 4 = — « : 5 i 16 Os i vel ; x ; ” al © a ‘ 4 y 14 9 4 e 7 Oo - ; « = . bl oh ee 5 Se 4 < i >» we we ? , ‘ ® 5 | her j a“ 4 4 s 4, @ 7 . : ¥ s : » “oh 2 ees ° " ei) n = >a a oy a : hy A! i> ‘. « Se a i. y F i PS % Aa fe, a ——F 4 —— . es > Le > «Yee! ras e oy - 46% ~ ain ) we ® J — lise pty ea we | ~ é if 9 . - > E aa ; ~ <©@ Pa 1? “sp AS aie 7 . rire - on, ; rh ar Pie oe - +S 6 : Lan al a PLATE IV A. ALTA OVERTHRUST AND GEOLOGIC EXPOSURES ON THE NORTH SLOPE OF LITTLE COTTONWOOD CANYON Showing the duplication of beds. Looking north 8. NEAR VIEW OF THE EAST-SLOPING ALGONKIAN QUARTZITE SHOWN ON THE RIDGE OF FIG. A e Showing the crumpled layers of hard quartzite ® n y ~~ oS H ; Ofer a a et ae. aR ay met ny OTT FO | Saas ed a Hey on ANNALS N. Y. ACAD. SCI. VOLUME XXIII, Puare 1V PLATE V TOPOGRAPHIC MAP OF THE ALTA REGION, WASATCH MOUNTAINS, UTAH The southwestern part of the Cottonwood Special Sheet, U. S. Geological Survey ‘ jean ‘ ya! Ms e ' / h \ j y, ¥ ‘ te al | mee , ae : . mrt ' . . 4 Wiese wt hg ay HAYO CWIATHUOM HOTARAW OIDs ATLA SET 30 TAM OTN gs it a i) , : , ‘ - aes . : ; Te cape hu be oc ee es sob tat Sapien tat hae ’ a . On @ Ka - ” (a = « TINN/LALIDA VE FTVINMPL xy A! eS “pp nx x Grad > a LW: Ye XX ~/ OFITIVA St SR SS 8 = 2 Aap thy 6 ae = = INL. Jpvisapps™ Y= | . SNIW : = ‘ i (gem agents . ff eAiyo ANS ! 7 7 ; — 4 CF} HEE. gy x We eae No/ g = Ss Se 2 = zee bad LOSS. \ ns ¥. = Yee a vat ® Z se x : Y nol ‘ CH? ie L&? ae Tz ee RAR, pee \ ( ( g tc © NV y asqito > « . | sah Oh ea } ) - J ) i “A / ig Vg ISAAK | f : ( A \ wh {uh Pail / y Y Tebohehy : \ ie PIO, \ sy7eM ¥O JONI fa ASS | Ve , | \ | | | | Mt ) ) \\ (i Cc ( \ x P| OH : ZY is 1}, WV KS Tey Yetors iiddaraante ‘ Mf > Fy — { ‘ \ av ; (x fi { " / We \ ‘ WON Si ee \ [x i \ | j 4 \ ‘ . \ LS KE Ln OR ed ’ ~ qu “ > - e ‘ CAN c | FN RRR (CC WN TL RRS ANS A i oe) SSN | cp / 5508 Ay I NUN al \ th | | YN CATON LOE ee ; Dike cZd | ‘ | Rif A) \ { eyed hn ; { xt | f > Ss Pa | ) / i / ) 15 if r\ : S74 Mi } Wi) ( } Y ( lan ) aye SSS THe 2 19 / \ \ ( | («! KE 4 / > \ JERVILU GIA + €¢ N \ \ Nk p . A ee ) / Qa ) ) " f ) —— Say \ A by P ( oS \)s f { ( « » A Ne 4) : OC SSI WRAL N en| { i AN > Dy) ) yeti yn SHS ge jaa ' 7 \ / ] . / | os = AS \ ( AER Vt ary y ¢ S + ‘A G 4 « ~ > 74 +s ’ ° a2 ‘ fad = ae, & — 7 * ~ 4° ‘ - By ~ Po 7 - ' - i ras) . ‘ a | «7 ¥ fd ° ‘ ’ a s » i ” : - ANNALS N. Y. ACAD. SCI. VoLuMr XNIII, Prater V J SMONTE CRIBTO Li. ~ =, Z : z < vae(y MINE Nin © - =F . ¥ . x (i “ = a - 2, ia La Bye hs a Scenre (iat EM NEL Soe Mere Tes £ =, Sf PHT SBOR: =e a go SS SILVER DIPPER — AINE ¥ PLATE VI GEOLOGIC MAP OF THE ALTA REGION, WASATCH MOUNTAINS, UTAH With structure sections, showing the relation of the Superior fault to the Alta overthrust * oar g 7 uw . ea : E a odt of dInet roiteque od3 40 a, So ph % eat a yar’ at oe eile soelad ate diane wh * a - 4 e ; P ‘ a 7 : Za a es “y . a ae! ~*~.) i , e a ub, ' e » : : 2 ‘ r 5 q 7 - | > © . 1% > {, z - Ls i-s a , of? hi @ = = Pa te ~M « » P * ‘4 . 7 « 7 '’ 7 a te = Ld a - _* 4 1 is h : P - . at a 4 , - 4 4 r ~ 4 * -~ » , ThA, wes ’ AS: ' s ¢ ; Ty . . ' ' ' » . - ‘ i = : 7 a ' a * ao , 1 . ‘ - é wy + V8 “ , ' ™ ind Lao . . "i er , i _# Ps <<“ «< t _ o? 1 » LES “aN } Algonkian Post-Carboniferous | ee 24\U019 Sea @4|10|p-OU015 Ar Sy0A O41 Aw f auizp4ony =< ee ZS | PS Lp ee ajous \ Savi0js 14} Bes $8 o8 5 eae #38 |pawiyuasaysipun Se 2}S0M 420Y Ear] Ve seivane Oe) 6) 2) 0) a/S1 8 Ceo Oo ty Shuasiened Te Ses BITC) x Dome eter creo Je = een LTA CONSOLIDATED a1yz4J4ony ARK 7 SS [Mie-< = ae -% s Lf E a - a a = 4 “ J a. ~ >. ¥ % we ee re ee , ' t re 7 R “euorstinod1aD-t20%, . . a . —< - .* ; . 4 a ; ¥ J ‘ - E : ; TF eg ee ee es eee ’ (KS > os mcr Le hte Pd at SV UvennwwWeWtege ts RL bry wef ie fig Ba, : 7 ay a? “4 ge ie i et ed Se ae Pe ey ae 4 i { PUBLICATIONS OF THE NEW YORK ACADEMY OF SCIENCES (Lyceum or Natura History, 1817-1876) The publications of the Academy consist of two series, viz. : (1) The Annals (octavo series), established in 1823, contain the scientific contributions and reports of researches, together with the rec- _ords of meetings and similar matter. 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Crampton, American Museum Recording Secretary—EpMuND Otis Hovey, American Museum Treasurer—HeEnry L. DoueErty, 60 Wall Street Inbrarian—RauPuH W. Tower, American Museum EHditor—Epmunp Otis Hovey, American Museum SECTION OF GEOLOGY AND MINERALOGY Chatrman—J. E. WoopMan, N. Y. University Secretary—A. B, Pactnt, 147 Varick Street SHCTION OF BIOLOGY Chairman—W. D. MarrHmw, American Museum - Secretary—WitiiaAmM K. Grecory, American Museum SECTION OF ASTRONOMY, PHYSICS AND CHEMISTRY Chairman—CuHar_es LANE Poor, Columbia University Secretary—C. C. TRowBripGE, Columbia University SECTION OF ANTHROPOLOGY AND PSYCHOLOGY Chairman—WENDELL T. BusH, 1 West 64th Street Secretary—Roxsert H. Lowi, American Museum The sessions of the Academy are held on Monday evenings at 8:15 o’clock from October to May, inclusive, at the American Museum of Natural History, 77th Street and Central Park, West. [ ANNALS N. Y. Acap. Scr., Vol. XXIII, pp. 145-176, Pl. VII. 27 January, 1914] LOCKATONG FORMATION OF THE TRIASSIC OF NEW JERSEY AND PENNSYLVANIA?* By A. C. HAWKINS (Presented by title before the Academy, 29 September, 1913) CONTENTS Page MA eR ee SS pete. © & sin he aoavGra es Woe aa mien oes os owas aw cele awed en ew wie 145 EI ae es Se ee ee ee ea 146 Distribution and topography....... 6... cece eee eee eee ee eee eens 146 NNR eR les AS Kars Sh pin dnics & bic) 54 'ej3¢m im O\ni is (B}a'¥ 6 Dev dialer Ble ele wa 147 te eh ee ea vio rs ices Roa Sw as ss Ceid nig pale ea eale eee 149 Re SR ere oa hd dig sab m8 SSID Sb Ce sae © oe cie nw Bidelen woe ele 80 151 RM IIIERE PRE TIITSUT Yor 02 oo, Fc enero n sw ele c\sene dias sence se wae wlale apace ee 155 ererminations of irom in the Lockatong argillites.............0cec.ceee 156 Le ee ore aa Meh eaet re SES oY uel hua afin iad-@ Wialre te inate 158 ee em ecmrara ghd UM EG: SECON GS 2... csc « ws 3 wwe sore ww eee renin eet a sacle 163 ee NS alee ig ac dn cute, ¢ wip’ Ae aie a0 oe Sele dh wos ae 166 odin rie als w ole kad gc ee ars Ree we a eee ee 172 EE EE TEI a 172 reer gfe eet a NE Seb ne Ue ees ia ew iln' sain wel eee ae ae ees 173 INCE CE Gureaer ea ot har hohe Gas Glas fapalle wee biked Vane ecliniein viele we bee 175 INTRODUCTION The study of a recently exposed zone of mineralization in an argillite quarry at Princeton, New Jersey, led the writer to extend his investiga- tions to certain interesting features of the rock formations and general tectonics of the region, a full knowledge of which was found to be essen- tial to the elucidation of the original problem. The statements herein made are based largely upon observations made during personal field work by the writer from 1910 to 1912. These data have been supplemented by additional facts supplied in publications of the State and national geological surveys, and by work in the petro- graphical and chemical laboratories of Princeton University. A bibliography of the publications that furnish the most important references is to be found at the close of this paper. Grateful acknowledgment is hereby made to those who have in various ways aided in the accomplishment of this work, including members of 1 Manuscript received by the Editor, 23 September, 1913. (145) LER nian | Thst Stiigo~. A 146 ANNALS NEW YORK ACADEMY OF SCIENCES the faculty of the Department of Geology at Princeton University, Dr. Edgar T. Wherry of Lehigh University and Dr. L. Hussakof of the American Museum of Natural History, New York City. HIsTorRY The Lockatong formation is the middle member of the sedimentary series of the Triassic system, as exposed in the adjacent parts of New Jersey and Pennsylvania. Elsewhere throughout the Triassic of eastern North America it is unknown. The earliest reports dealing with the rocks of this formation mention them only in connection with the quarrying industry of the region. Thus, in the Annual Report of the State Geologist of New Jersey for_ 1880 (p. 24), a short statement is made concerning Stephen Margerum’s quarry in Princeton, which was first opened in 1845. In the issue of this publication for the following year (p. 55), a similar allusion appears. F. L. Nason’s discoveries of: fossils from the Triassic, reported in 1888 (idem, p. 28), include those found in the Lockatong beds. B.S. Ly- man? wrote a report on the New Red of Bucks and Montgomery Coun- ties, in which the rocks of this middle member are described and named Gwynedd shales. Because however this term was made, on the map at least, to cover rocks clearly referable to other formations, it seemed best to the New Jersey geologists to rename the formation, and in the de- tailed report Dr. H. B. Kiimmel* proposed the term Lockatong, which is now generally used. This was further supplemented by an even more detailed paper, published by him in his report for the following year.* In 1908, Professor J. Volney Lewis made a careful investigation of the argillites of this series, the results of which were published in the State Geologist’s Report for that year (p. 94). Since that time, descriptions of the Lockatong have appeared in the Philadelphia Folio (No. 162), and in the Trenton Folio (No. 167), of the United States Geological Survey, in both of which excellent geological maps of the respective areas are given. DISTRIBUTION AND ‘TOPOGRAPHY The rocks of this series lie in a slightly curved belt extending from a point some ten miles west of Phoenixville, Pa., to the border of the Cre- taceous formation about ten miles northeast of Princeton, N. J. (See 2Summary Final Report of the Second Pennsylvania Geological Survey, vol. 3, part 2, p. 2610. 1895. 3 Rept. State Geologist of N. J., 1896, p. 40. 4 ITbid., 1897, p. 36. * HAWKINS, LOCKATONG FORMATION OF THE TRIASSIC 147 Plate VII.) The general trend of the belt is thus northeast and south- west, in harmony with that of the local Triassic in particular, and that of the pre-Triassic rocks and of the Appalachian highlands in general. The course of the Lockatong belt is usually marked by a ridge whose long axis corresponds with the strike of the formation. This ridge com- monly has a relief of fifty to a hundred feet or more above the surround- ing Triassic area, which is underlain by the somewhat less resistant rocks of the Stockton and Brunswick series. At Phoenixville, it is traversed by two railroad lines, which cross it by means of open cuts and tunnels. Three railroads cross it between this point and the Delaware River, and each of these has required much excavation, At Byram, Hunterdon Co., 'N. J., there is a long, persistent series of bluffs flanking the river for a distance of four miles, the cliffs at certain places being exceedingly steep and rugged. Between the Delaware and Princeton the topographic effects are not so pronounced. At Princeton the hard rocks, though not very thick, form a ridge, upon which the town has been built. Upon the Lockatong ridge there is a heavy yellow clay soil, which is typical of the formation. In it are seen many irregular, splintery frag- ments of resistant dark-colored shale and argillite. These argillite frag- ments, after a considerable period of exposure to the air, often develop a brown or yellow greasy surface, due to the production of kaolin, which gives rise to the typical sour soils of this belt. These soils, however, are fertile. The high land overlying the Lockatong beds supports an abun- dance of timber, which, throughout much of the area, has been cleared away to make room for prosperous farms. The drainage is active, and most of the larger streams cut directly across the hard rock ridge. STRATIGRAPHY The portion of the Triassic system exposed in this part of the country, usually referred to as the Newark, is composed of three distinct parts or units, which, named in order from the bottom to the top of the series, are the Stockton, the Lockatong and the Brunswick formations. The Stockton formation is composed of coarse conglomeratic sandstones of light colors, usually interstratified with red shaly beds. The Lockatong series of dark-colored, fine grained mud-rocks is the one herein described. The Brunswick formation consists of a very thick succession of red shale beds with some portions that are heavy bedded sandstones, and some- times well developed conglomerates. The total thickness of the Triassic rocks in New Jersey is estimated to be 18,000 feet. The larger portion of this thickness is made up of red or reddish brown shaly and sandy 148 ANNALS NEW YORK ACADEMY OF SCIENCES rocks. The dip, which is fairly constant, averages about 15 degrees northwest, which is normal for the whole system in this vicinity.® The Lockatong formation is thickest in the middle portion of the belt, as appears very plainly when the whole belt is mapped together (Pl. VII and Fig. 1, p. 149). Exposures along the Delaware River® fur- ther prove that it steadily thickens for some distance westward. Sections of the formation are shown by the river at an average distance of eight miles apart, east and west, on account of the repetition of the beds due to the great Flemington and Hopewell faults, which together have a throw of approximately 17,000 feet. West of Phoenixville, the Locka- tong rapidly narrows and finally terminates in a thin edge, its horizon being taken by a heavy conglomerate, apparently of Brunswick age. Northeast of Princeton it narrows considerably; northward of this point, it is hidden beneath a covering of later sediments of Cretaceous and Pleistocene age. Its total failure to re-appear twenty miles farther north, where only the softest of red shales are exposed, has led to the belief that its northward termination is perhaps much like the southern one west of Phcenixville. From these observations, it appears that the Lockatong is a deposit of a decidedly lens-like character. A comparison of the area of the Stockton formation with that of the Lockatong, throughout the extent of the latter, shows that the Stockton varies with the Lockatong, widening and narrowing with it. The Lockatong consists of a thick series of exceedingly fine grained and close textured rocks. The sediments were so thoroughly sorted that scarcely a single coarse textured layer is to be observed among them in the field. The rocks as they now exist appear as massive, fine grained argillites and shales, the former, on account of jointing, often forming “flagstones” or more massive blocks. The “slates” are often friable, having a cleavage which is too uneven to afford good roofing slate. The color of the shales and of the argillites may be gray, reddish brown, black, or olive green. Red and gray colors often alternate on a large scale. Impure limestone layers one or two inches thick occasionally appear. The bedding of the Lockatong argillites and shales is very uniform, although a slight irregularity is sometimes present in the bedding of shaly layers. No cross-bedding appears. Ripple marks and mud-cracks occur, the latter sometimes abundantly, in the upper and lower portions of the series. ® 5A detailed description of this series is given in the Trenton Folio, No. 167, United States Geological Survey, p. 7. 6 Tbid., Geological map. HAWKINS, LOCKATONG FORMATION OF THE TRIASSIC 149 LOCK ATONG FORMATION BRUNSWICK STOCKTON TORMATIONS iG. 1.—Geological sections across the Lockatong formation from northeast to southwest Where continuous exposures are available near Princeton, the succession of beds usually can be ob- served to be about as follows: At the lowest portion of the section examined (as in McCarthy’s quarry, Princeton) there is a thick series of strata of dense, reddish brown, flaggy argillite. At its upper limit the brown bed suddenly loses its characteristic color, and passes, without change in other respects, into a dark gray rock, the most typical argillite of the series. A short distance higher up in the dense gray rock, radiating crystal growths occupy a horizon about a foot thick, with irregularly scattered white crystal specks in the layer immediately above, as hereafter described. Above this horizon there is apt to be an inch or so of very black, carbonaceous shale, followed by one or two inches of a light gray, thoroughly crys- talline magnesian limestone. This is again succeeded by an inch of black shale, above which there are gray argillite beds. Still higher more red rocks may ap- pear, and the whole series, as above described, may be repeated. COLUMNAR SECTIONS Columnar sections of the Lockatong series are shown in Fig. 1. The,sections are numbered from 1 to 7, beginning at the west. They are arranged im order of occurrence, being spaced at approximately correct relative distances horizontally. The vertical. scale is made, for convenience, ten times the horizon-- tal. The datum plane selected for correlation of the: various sections is the top of the massive argzllites,.. whose deposition marked the time of steadiest sedi-- mentation and most sluggish drainage, which in turn: signifies a nearly level surface throughout the area.. It is to be noted that this arrangement brings the: prominent Hstheria beds, near the base of the three western sections, to about the same level. The transi- tion beds are represented by black bands where they occur, in the upper and lower part of each section, and the outline of the basin has been completed to show how a repeated interdigitation of the Stockton 150 ANNALS NEW YORK ACADEMY OF SCIENCES below and the Brunswick above with the Lockatong might account for the areas of transition. 0. This part of the basin is underlain by dark-colored shales; no argillites appear. At the western end there is a heavy conglomerate, probably of Brunswick age. 4. Reading Railroad tunnel section, Phenizville. Feet Shale; dark red. to:black (top bed). sce eet sis estoie ease tecdaysue eas rena 380 Shale: WrOwW A «(chi iosc s ols Bese eee oleic s ne vetars) ale OMe ee pec ee eee 380 Argvillite, “Drow: 2s). sccis scar eheke ¢are cere tiene breve serene ate tec tcy aceon 250 Whaile,..sandy, red and HOW 4) 6.2 a 50k ees © Oleiere ee encte toa iatel Gemebieae (Black shales with eStheriees jz sic saccyal siete sine tae 10s sere pol ouerereuenete sete ene veeel arene | 490 Shale, red and brown, transition beds (bottom bed)............. J Total, (no: important fanliimey! oe la eater rene inrenere eat 1500 2. Schuylkill River section, Phenizville. Shale-and argillite, brown: (top, bed)... sheik s see ee eee 750 Shale, black, with fish seales......... Ls creck nslie ele ouctelo ntete Cieenec nec: tear 5O ALOU Wite, DROW sii.\s oeseevel dG eee eter ene owe ere nteseer abate cele tous tehateds lokeacieesreretcuemcian: 500 Shale: ‘dark ‘colored; ‘wathvesthertee:. ..:.02%, an et eid cee ie oe oh oe ee ees 20 Shale; dark red “Gbottorn MOG) ei22.c Giaie s:cyeucea ions ecu ehtexecctiepone cote or oereieteeattale 380 ‘Potal CuO: Lait We). 2 cites eleven foreun eens Seve carete erereonate aden teens 1700 3. Perkiomen Railroad section. Shale; dark red’ (iGp Ded: sos oes ort ah @ acini wie ae Oe See eee 750 ATU Ce, DEO WARE 24, deacenial 65) ays Gre coropslins ene taneun tee ores ve pote Teneo eeere ne tae pene 500 BOIS) Wit CSUSB aye se 5 ce! pihs io eau sah Ses) atatichicllc havens ious oxcleya eater eiele neue io tee eae 10 AT OUNCES, LOW r.)<, 5.0 5000 wate we Gr heist whee ein ere ello eleva Nee meten Crete event ae 330 shale, bard andined 2.4. sine ¢olek posececie oes eve ee einie seek: Ree 330 Shale, ray, With esther: .c.c-+.ccastee nts See eke aches Oe Gee ee 10 Shale, dark red -«Gbottom) Ded): ..6o0..s.c sie sista erectus ee ee einen 200 Probably no important faulting. FPO CAI oa dba cu eee Peiees NG: a leller Dis oie Ihe ee tele eS Tete SEER nse eee 2140 4. Gwynedd Valley section, Philadelphia and Reading Railroad. Shale, dark: red-(top DEG)... sols oe aie Reena a Geeta © cuerte ere career 720 ATAU Ce, DEO Wize pve dynes ie loss 0 4 soe fale seta ec ead ORE ete ie ee Clee nie See 1000 Shale ‘dark red ‘(bottom Bed) c.......-c.0seuute sites seit eee 1000 10 per cent reduction made for faults. POCA a 5 5 Fle ioG) eerste dere eve by foes erate Rnoeaicane tp paitete tea ain de Rite oan nedt ye area 2430 5. Wycombe section, Philadelphia and Reading Railroad. Shale, dark red. (top DEG): skisde eens tee oleae tice treater 670 Limy layer with estherizw, scales and ostracodS...............20- 1 Arcillite, gray Ani IDKOW foes. hace cic bis sit were dare laies Meares ieee rate eee eee 1000 Argillite, with magnesian Jimestone Dands2: ..).),.2)) 0.26 eee eee 50 Shale, POW. aiccie wisn So see age onus area ayer ARO MOTE eRe inn one 600 HAL], TODS sale eee ole c Scrat ror tue te coy Sesletameoethn lettatcat Saket ie anne en ene ae 450 HAWKINS, LOCKATONG FORMATION OF THE TRIASSIC 151 Feet Senda Deus, STECM ANG FOMOW nace ee wel ve ob Seis bce wmalsieg ss 60 Arcillite and shale, hard and red (bottom bed)..........6..c00.0: 190 Fault of 1000 feet at the top. 10 per cent reduction made for other (undetected) faults. LS | pele BE ES EN Re AL So a 2700 6. Scudders Falls section, Delaware River. Shale, dark colors, alternating at top with red shale (top bed).... Per UTGCe UAC TNL SPMEEIG: sro leicin chee rleis osetel ciara s,5 a ait none ea ee agate acess Oe © SAE ML GE TORI thy hc cate Mayet as aie ee Pees) etans, of tate eal Ste (aia, wt eote ie