214 GEOLOGICAL SURVEY OF THE TERRITORIES. 



The specific name is given in honor of Dr. Endlich,of the United 

 States geological survey of the Territories. 



Location and position. — East of Animas Eiver, Colorado Territory, 

 where it occurs associated with a small Productus of the type of P. sub- 

 aculeatus. According to Dr. Endlich's sections, as well as from its 

 afifinities, it would seem to be most properly of an Upper Devonian spe- 

 cies. Fragments of it have been brought in from other localities in the 

 Eocky Mountains. 



As mentioned before, the Devonian strata extend from station 48 in a 

 northwesterly direction, reaching nearly to the edge of a canon that 

 separates the main mass of the Quartzite Mountains I'rom the sedimen- 

 tary area. A number of points along this line of outcrop are the high- 

 est on the sedimentary ridges. True to the general character of the 

 stratigraphy of that region, the beds dip off to the south and southwest, 

 at an angle varying from two to six degrees. So far as could be deter- 

 mined, the strata show very nearly the same condition in the other 

 portions of the Devonian area, as they were described from station 48. 



A section taken from station 48 to station 49 (section I,) which is located 

 on Lower Carboniferous strata, will show the relations of the sedimentary 

 beds to the underlying metamorphics. Under the granite a shistose rock 

 sets in, a, that is merely a continuation of the large masses occurring near 

 the borders of the quartzites. Above it follows the stratoid grauite &, 

 dipping off to the south and southwest conlormably with the overlying 

 beds. The quartzite sets in then and continues to the southward, c. 

 Ascending higher, we reach the siliceous shales, d, containing the pseu- 

 domorphs of salt and the remains of fish. Blue limestone, e, forms the 

 capping of the small plateau upon which station 48 is located, and, as 

 well as the rest, continues southward, growing thicker, however. Above 

 this the Carboniferous beds set in. The entire thickness of the sedimen- 

 taries at station 48 amounts to about two hundred feet, while farther 

 south the limestone, e, alone reaches that figure. Horizons for fossils, 

 that were observed along the bluffs south of station 48, let itappearthatthe 

 stratum covering that point must ha ve been either eroded or must have dis- 

 appeared in consequence of the activity that produced the metamorphic 

 rocks. Comparing the thicknesses we find here with those observed on 

 Lime Creek, the striking difference will be observed at once. A very 

 large portion of the Devonian strata has been converted into coarse- 

 grained grauite near station 48. I see no reason to assume that the de- 

 position at that point was less in thickness than twenty miles farther to 

 the northwest. These two localities exhaust the outcrops of Devonian 

 rocks in our district. Their relations to overlying formations are very 

 simple, having a conformable stratification. 



' . CAEBONrPEROUS. 



Members belonging to this formation cover a great deal more ground 

 than those of the preceding groap. It is mainly divided into two divis- 

 ions, the Lower ('arboniferous, and the Upper, containing the red sand- 

 stone. The former crops out all along the west side of the Animas, down 

 to about the middle of Animas Park, while on the east side of the Ani- 

 mas it forms a part of the higher ridges sloping off' southward from the 

 Devonian area of that region. Throughout the area which it c<5vers, its 

 stratigraphical relations conform entirely to those of the underlying De- 

 vonian rocks. Varied as the formation is, and notwithstanding its quite 

 considerable vertical development, but few localities were found where 

 characteristic fossils afforded any definite evidence regarding age. The 



