THE FLORISSANT LAKK HASIN. 25 



probable from the kaolinized feldspars and (lit- macroscopie fragments of apparently 

 older roeks tliar the latter are present in the tufa to some extent. This can best be 

 explained by the supposition that it was deposited as a nn>i/ti or mndllow within n-ach 

 of the .vaters that have worked it over and deposited it in its present position. As we 

 said before, the field evidi-nee must be relied upon inaiulv in deciding such questions 

 as ihe-r. 



M. K. WADSWORTH. 



<'AMI;I:IIH.I:. MASS \< in si: ITS. April !.">. issn. 



Another section, less carefully measured and noted with less detail than 

 the other, was taken at tin- extremity ot one of the promontories jutting in 

 a southwesterly direction into the middle of the upper chain ol' lakes, about 

 ilm-i- kilometers west ol' the present post-office. The top of the hill was 

 coyered with granitic ^ravi-l and loose bowlders of dark scoriae-eons trachyte; 

 In-low this we found, passing, as before, from above downward, the following 

 succession : 



SECTION IN I UK NORTHWKSTKUN LAKE. 



S. II. .v n,l,l,r ami .1. Lakes.) 



Decimeters 

 (estimated). 



1. Fini-ly laminati-d \ i- 1 low-dra 1 1 shales; no fossils 1-J 



2. i oars,' decomposing yellowish shales ; mi t'u-sils 12 



:>. Fine compact ciraii shale-, : pn i, rt remains of plants and inserts 15 



i. Arenaoeons shales; vi-ry li^nitic 6 



.'. lli-avily ln'cidril, co:irsi'-^;raiiii-il, orombliDg .sandstone, of a grayish-yellow aud whitish rnlur, be- 



ciiiiiin^ l<>n Heinous inplaci-s: partially li^n it ir (!() 



6. Cliurulatc anil drali t-olnrrd shalrs having a rom-hnidal fracture, passing below iutu whitish paper- 

 like shales inclosed between coarse arenaceous lamina' ;. plants aud insects 45 



Total thickness of shales almve tlnor deposits, i Meti-rs, estimated) 15 



These measurements, being estimated, are undoubtedly too great, The 

 composition of this bluff is coarser in character than that of the section in 

 the southern extension of the lake. The lignitic beds, which have been 

 ii>rd for quarr\ing purposes, contain numerous fragments of reeds and 

 roots not well preserved. The lower portions of the section correspond 

 better with the other than do the upper beds, where it is difficult to trace 

 any correspondence ; No. 3 of the northwestern seems, however, to corre- 

 spond to No. 16 of the southern series. The whitish paper shales lying at 

 the base of this appear to be entirely absent from the southern section, and 

 the distorted beds which crown the mesa are not apparent in the bluff, or, 

 if present, are wholly regular. A more careful and detailed section of the 

 bluff (for which we had not time), and particularly the tracing of the beds 

 along the wall of the lake, would probably bring to light better correspond- 

 ences. 



