THE FLORISSANT LAKE «ASIN. 21 



Our examination of the deposits of this lacustrine basin was principally 

 made in a small hill, from which perhaps the largest number of fossils have 

 been taken, lying just south of the house of Mr. Adam Hill, now owned 

 by Mr. Thompson, and upon his ranch. Like the other ancient islets of this 

 upland lake, it now forms a mesa or flat-topped hill about ten or a dozen 

 meters high, perhaps a hundred meters long and twenty-five broad. Around 

 its eastern base are some of the famoiis petrified trees — huge, upright trunks, 

 standing as they grew, which are reported to have been five or six meters 

 high at the advent of the present residents of the region. Piecemeal they 

 liave been destroyed by vandal tourists, until now not one of them rises 

 more than a meter above the surface of the ground, and many of them are 

 entirely leveled; but their huge size is attested by the relics, the largest of 

 which can be seen to have been three or four meters in diameter. These 

 gigantic trees appear to be Sequoias, as far as can be told from thin sections 

 of the wood submitted to Dr. George L. Goodale. As is well known, re- 

 luains of more than one species of Sequoia have been found in the shales 

 at their base. 



At the opposite sloping end of this mesa a trench -was dug from top to 

 bottom to determine the character of the different layers, and the section 

 exposed was carefully measured and studied. In the work of digging this 

 trench we received the very ready and welcome assistance of our com- 

 panion, Mr. F. C. Bowditch, and of Mr. Hill. 



From what information we could gain about the wells in this neigh- 

 borhood and from a shaft sunk obliquely in the side of a hill near the 

 northwestern extremity, it would appear that the present bed of the ancient 

 Florissant lake is entirely similar in composition for at least ten meters below 

 the surface, consisting of heavily bedded non-fossiliferous shales, having a 

 conchoidal fracture. Above these basal deposits, on the slope of the hill, 

 we found the following series, from above downward, commencing with the 

 evenly bedded strata : 



SECTION IN SOUTHERN LAKE. 



(By S. H. Sciidder and A. Lakes.) 



Centimeters. 



1. Finely laminated, evenly bedded, light-gray shale; plants and insects scarce and poorly 



preserved .3.2 



2. Light-brown, soft and pliable, finegrained sandstone; unfossiliferoiis .5 



3. Coarser, ferruginous sandstone; uufossiliferous 3.8 



4. Resembling No. 1; leaves and insect remains 21 



5. Hard, compact, grayish-black shale, breaking with a conchoidal fracture, seamed in the 



middle with a narrow .strip of drab shale; fragments of plants 28 



