20 MEMOIBS OF THE NATIONAL ACADEMY OF SCIENCES. 



measurements having been taken, I quote the following account of it by Mr. G. K. Gilbert, in 

 his report " On the Geology of Portions of our Western Territory," visited in the years 1871, 1872, 

 and 1873:* 



Along many of the beaches, and especially at points where they a.re carved in solid rock, the beach or terrace 

 below the water-line is composed of calcareous tufa, usually full of small Gasteropod shells, and often involving so 

 many fragments of the contiguous rock as to constitute a breccia. In the localities where I found it best exhibited 

 the beach was carved in limestone, but the deposit is probably independent of the character of the adjacent forma- 

 tion. Mr. Howell observed it upon Granite Mountain, coating granite, and remote from limestone exposures; and a 

 similar association was seen by Prof. W. P. Blake on the Colorado Desert. Down some steep slopes it stretches as 

 an apron for several rods, and, when it rests on soft materials, the waves of the retiring lake have undermined it and 

 formed caves. Several of these are to be seen on the north end of the Oquirrh range, and the largest, which is popu- 

 larly reputed to have been excavated by Spaniards years ago as a mine, is remarkable as a specimen of purgatorial 

 wave-work. The Carboniferous strata have a local northward dip of 80°, and trend parallel to the face of the decliv- 

 ity. Two beds of limestone, which constitute the walls of the cavern, are separated 12 feet at the entrance and 

 evenly converge to the rear end, where they are 4 feet apart. At the end a shale, in place, fills the interval, but I was 

 unable to determine whether this had once occupied the entire excavated space. The root' is built entirely of recent 

 calcareous breccia, and the floor is evenly spread with earthy d6bris. The height of the gallery is uneven, ranging 

 from 2 to 25 feet, and the length is 275 feet. The breccia of the roof pertains to one beach of the great series, and 

 the floor is near the level of another. The wonderful depth of the excavation in a direction nearly parallel to the 

 shore is explained by the convergence of the straight walls, between which the waves gained in their progress, on 

 the principle of the hydraulic ram, enough velocity to compensate for the loss by friction. 



In order to feel entirely certain that the cave I examined was the same as the one thus 

 described, I wrote Mr. Gilbert, and received such information from him as placed the matter 

 beyond a doubt. 



The specimens occurred entirely under stones, none upon the walls, as the cave is perfectly 

 dry, a very slight degree of moisture gathering under the flat pieces of brecciated limestone, which 

 had fallen from the roof above. The darkness was not quite total, a faint glimmer of light appear- 

 ing, although it was necessary to use candles in exploring the cave as well as in searching for speci- 

 mens. Having previously examined a much larger cave in the Carboniferous formation in Williams 

 Canon at Manitou, Colorado, without finding any signs of indigenous life except Dielidia Icetula and 

 its larva, which occurred on the steps near the entrance, and which had been evidently a recent intro- 

 duction, I was much interested to find in this small isolated cave in Utah a well-marked cave fauna, 

 although not as characteristic as that inhabiting the caverns of Kentucky, Indiana, or Virginia. 

 Four forms occurred, of each of which several individuals were found in a few minutes' search. 



The spider-like form, Nemastoma troglodytes, belonging to the group of "harvestme^'' was per- 

 haps more abundant than the others. It belongs to a group not before known to inhabit North or 

 South America, none of the family occurring in caverns east of the Mississippi Kiver. Species of 

 the genus occur, however, in Europe. It had well-marked eyes. The Myriopod belongs to a widely- 

 distributed genus (Polydesmus), but which in this country has not been hitherto known to be a true 

 troglodyte. Like all the species of the genus, which as a rule live in the twilight under stones and 

 leaves, etc., it is eyeless. Its entirely white color, when all the other known species are highly col- 

 ored, shows that it is also a true cave-dweller. The Poduran (Tomocerus plumbeus) is found abun- 

 dantly in Europe, Greenland, and North America. It occurred of very large size under stones at an 

 elevation of 11,000 feet on Gray's Peak. It will probably be found on the Pacific coast. The indi- 

 viduals, however, discovered in Clinton's Cave, Utah, represented a white variety peculiar to cav- 

 erns, and which differed in no respect from bleached individuals found in the Carter caves of Grayson 

 County, Kentucky. A small Zonites was discovered, which was white. Its occurrence was of a 

 good deal of interest, from the fact that of the numerous Helices which occurred in the caves of 

 Kentucky none were bleached or differed notably from those found in their usual habitats, though 

 I am told by Prof. E. S. Morse that adult white individuals do occur in ordinary habitats. 



A high degree of interest attaches to this cave fauua, because we are able to determine with 

 much precision the period when the cave was made and the time of its subsequent colonization 

 by the ancestors of the present inhabitants. On turning up the loose material constituting the 

 bottom of the cave I found that it was largely composed of a shell-marl, in which occurred in 

 abundance little fresh-water shells, which the late Mr. G. W. Tryou determined as Amnicola decisa 



* Extracted from volume iii. of the United States Engineer Eepoits of Explorations and Surveys West of the 100th 

 Meridian, Lieut. G. M. Wheeler in charge. 



