194 REPORT UNITED STATES GEOLOGICAL SURVEY. 



the same general characteristics as that which is mined in the face of 

 Table Mountain, near Golden City, three or four miles away. 



Mr. W. H. Holmes, artist and geologist of the Survey, visited the place 

 about that time and collected a few specimens of a shell that Mr. Meek 

 afterward described as Cyrena f holmesi in the Bull. XJ. S. Geol. Surv. 

 Terr. 2d ser. No. 1, p. 45. 



The shells were found in the uppermost of the layers that were dug- 

 through in sinking the shaft, and, so far as I can learn, no other fossils 

 were found in any of the other layers. I was not able to learn at what 

 depth the coal was found beneath these fossiliferous layers, but it was 

 probably not more than fifty feet. The strata, as I saw them by looking 

 down the shaft, were alternating layers of soft and harder sandstone 

 with sandy shales, and the series of layers appeared, and are reported 

 to have been found without any material change from top to the coal 

 below. The debris and soil so completely cover the valley sides and its 

 neighborhood as to obscure all strata adjacent to those that were seen in 

 the shaft, and the surface presents no direct indication that the strata 

 beneath have ever been violently disturbed. Mr. Holmes, therefore, not 

 being in possession of the paleontological facts which I have since ascer- 

 tained, supposed the natural position of the fossils referred to, to be above 

 the bed of coal which is mined in Table Mountain, near Golden City, as 

 it was found now to be above the coal in the shaft.* 



A year or two after Mr. Holmes's examination of this district Mr. 

 Arthur Lakes also examined the strata of the then abandoned shaft, and 

 besides specimens of Cyrena 1 holmesi he found associated in the same 

 layer an unmistakable fragment of a Scapliites. According to our pres- 

 ent knowledge of the geological range of this genus, this discovery is 

 assumed to show conclusively the Cretaceous age of the strata in ques- 

 tion. This specimen is too imperfect for full specific identification, but 

 it seems to belong to 8. mandanensis Morton, which indicates the epoch 

 of the Fox Hills Group. As there seemed to be no stratigraphical break 

 between the layers containing the fossils and those in contact with the 

 coal, the latter has been inferred to be of Cretaceous age also ; but the 

 following difficulties are in the way of such a conclusion : 



Notwithstanding the fact that west of the Bocky Mountains coal 

 has been found in both the Fox Hills and Colorado groups, so far as I 

 am aware no indication whatever of coal has yet been found in the 

 strata of either of those groups, nor in any strata older than those of the 

 Laramie Group, east of the Bocky Mountains in Colorado. All the 

 Mesozoic strata known in this region are well exposed in this immediate 

 neighborhood, and they have been carefully explored for coal without 

 success. Again, some small masses of compact calcareous rock were ob- 

 tained from Mr. Geo. L. Taylor of Denver, Colo., labeled, " From near 

 Colorado Springs, Col." These were filled with shells almost certainly 

 identical with the Cyrena? holmesi of Meek, and imbedded among them 

 I found a fragment of a gasteropod having the characteristics of Lunatia 

 so far as they could be ascertained. This is the history of the perplexing 

 discovery at Balston Creek at the time of my visit there in 1877. 



Being in possession of the foregoing paleontological facts I could not 

 accept the reference to Laramie or later age of the strata containing 

 Cyrena f holmesi, and I made as careful an examination as possible of 

 that neighborhood with a view to a proper understanding of the true 

 condition of the strata there, and with the following result : 



* So far as I am aware, Mr. Holmes never published his observations in this district, 

 and the view he then held is inferred from the statement made by Mr. Meek in con- 

 nection with his description of Cyrena? holmesi (loc. cit.). 



