134 GEOLOGICAL DISTRIBUTION. 



they occurred only rarely or in fragments. Plants were always abundant 

 where insects were found, but also occurred in many strata where insects 

 were either not discovered — such as beds 18 and 21 in the lower half and 

 bed 6 in the upper half — or were rare, as in beds 10 and 14 above the 

 middle and bed 23 below; the coarser lignites occurred only near the base. 



•• The thickest unfossiliferous beds, Nos. 20 and 27, were almost uni- 

 form in character throughout, and did not readily split into laminae, indi- 

 cating an enormous shower of ashes or a mud-flow at the time of their 

 deposition; their character was similar to that of the floor-beds of the 

 basin. 



"These beds of shale vary in color from yellow to dark brown. Above 

 them all lay, as already stated, from 4 to 6 feet of coarser more granulated 

 sediments, all but the lower bed broken up and greatly contorted. These 

 reached almost to the summit of the mesa, which was strewn with granitic 

 gravel and a few pebbles of lava.'" 



The specimens of Florissant representing the plants described in this 

 memoir were mostly obtained by Professor Scudder, who had opportunity 

 to purchase for Dr. Hayden a collection made by Mrs. Charlotte Hill, the 

 proprietress of the land where are exposed the banks containing the 

 richest fossiliferous shale. A little later a scientific exploration for the 

 College of Princeton visited the same locality and obtained there also a 

 great number of specimens; some of these, very fine, which were loaned 

 me for examination, have been figured and described in this report. I 

 have been allowed to use the names of some of the members of the 

 exploration — Messrs. W. B. Scott, H. F. Osborn, F. Speir, McCosh, W. 

 Libbey — for the nomenclature of some of the new species which are 

 represented by the Princeton specimens. 



