54 



LARAMIE FLORA OF THE DENVER BASIN. 



On the east side of the Crazy Mountains 

 Stone, starting with the I'pper Cretaceous 

 section as established on Fish Creek by Stanton 

 and Hatcher, held that he was able to trace the 

 heavy whitish Eagle sandstone around the 

 north end of the mountains and thence along 

 the eastern base of the Bridger Range to a 

 point above Clyde Park, which was sub- 

 sequentl}- connected by Calvert, except for a 

 number of covered areas believed by him to 

 be unimportant, with the coal measures near 

 Livingston. The other units of the Montana 

 group (Claggett, Judith River, and Bearpaw) 

 were differentiated with more or less certainty 

 to the vicinity of Lcnnep, just east of the 

 Crazy Mountains, but they disappear at the 

 north end of the mountains and southward 

 along the Bridger Range, the southernmost 

 point at which either has been identified being 

 about 10 miles north of Myersburg, or 40 miles 

 north of Livingston, where the upper part of 

 the Bearpaw was seen. It was argued by 

 Stone and Calvert that south of Myersburg the 

 Montana section interdigitates with and loses 

 its identity in the thick Livingston beds near 

 the type locality. Their conclusion was as 

 follows : 



A great thickness of sedimentary deposits occurring at 

 Livingston, Mont., composed largely of tuffaceous mate- 

 rial, has been called the Li\ingston formation. It is de- 

 scribed as Ij-ing unconformably on coal-bearing sandstone 

 of Laramie age. 



The evidence, both from stratigraphy and invertebrate 

 paleontology, submitted in these pages shows that the coal- 

 bearing sandstone is Eagle or at least lower Montana in age. 

 It is admitted by paleobotanists that the flora of the upper 



part of the coal-bearing beds is similar to the Livingston 

 flora, the greater part of which comes from within 600 feet 

 above the coal-bearing sandstone. The coal-bearing beds 

 are transitional into the tuffaceous beds above. Therefore, 

 the evidence of both stratigraphy and paleobotany indi- 

 cates that the Livingston beds are conformable on the 

 underljing coal-bearing beds. 



The Livingston formation was originally described as a 

 lithologic unit of tuffaceous material derived from volcanic 

 activity, the material of which the beds are composed and 

 not the fossils determining the extent of the formation, 

 Beds of this character are most abundant in the Livingston 

 region, but they have been traced north and east around 

 the (!'razy Mountains, where beds of similar lithology are 

 found in all the formations from Colorado to Fort Vnion 

 and where they feather out into and merge with fresh and 

 brackish water and marine deposits. 



Slratigraphic relations, marine invertebrates, and fossil 

 plants prove the Montana age of the lower part of the tuffa- 

 ceous bods on the west side of the Crazy Mountains origi- 

 nally mapped by Weed as Livingston, Northeast of the 

 mountains some of the tuffaceous beds are younger than 

 Bearpaw and older than Lance, while the youngest of the 

 andesitic deposits are Fort L'nion. From this evidence it 

 is concluded that the lithologic unit of tuffaceous deposits 

 originally described as the Livingston formation has no 

 definite age and no formational value except in the imme- 

 diate vicinity of the type locality, 



I dissent from the above conclusions and 

 still hold that the Livingston, at least in the 

 type area, is of post-Montana age. 



In 1912 Calvert" published two short re- 

 ports on the southern portion of the area in- 

 cluding the Livingston, Trail Creek, and Elec- 

 tric coal fields. His conclusions are sufficiently 

 set forth in the following generalized section : 



« Calvert, W, R., The Livingston aod Trail Creek coal fields, Park, 

 Gallatin, and Sweetgrass counties, Mont.: U. S. Geol. Survey Bull. 471, 

 pp. 3S4-405, 1912; The Electric coal field. Park County, Mont.: Idem, 

 pp. 406 422. 



Geologic formations in the Livingston district. 



