246 W. N. LOGAN 
uniformly greenish color. The following fossils occur in it: 
Camptonectes bellistriatus Meek; Camptonectes extenuatus M. & H.; 
Gryphea calceola var. nebrascensis M. & H.; Ostrea strigilecula 
White and Ostrea densa Logan. 
15. Purplish clay containing considerable arenaceous inclu- 
sions, 40’. The clay contains in the upper part a thin strata of 
sandy limestone in which the following fossils were found: 
Pentacrinus astericus M. & H.; Asterias dubium White; Pseudomo- 
notis curta Hall; Avicula macronatus M.& H.; and Ostrea strigile- 
cula White. 
Como beds.—The last stratum is the uppermost one, containing 
marine fossils and probably closes the Jura. The succeeding 
layer varies so much in thickness within short distances that it 
may represent the slightly eroded surface upon which the Como 
beds were deposited. 
“16. Fine-grained, grayish-white sandstone, 10’ to125’. The 
above stratum varies much in thickness within short distances. 
At one point on the Dyer Ranch it has a thickness of 10’, while 
a few miles southeast of that point it reaches a thickness of 125’. 
The sandstone composing the layer is of nearly uniform color 
and texture. Its induration is only moderate, and it weathers 
into many grotesque forms. Cross-bedding is well exhibited by 
it in many localities. 
17. Purple to greenish colored clay, 60’. This is apparently 
an unfossiliferous layer except in the uppermost horizon, where 
species of Dinosaurs belonging to the genera Avontosaurus and 
Morosaurus occur. This is the lowest fossiliferous horizon of the 
Como beds and the beds included between this horizon and the 
layer marked 15 may represent the transition from marine to 
non-marine conditions. 
ids, sandstones orayishw to ight brown, lO) tonZo) elite 
above sandstone presents some very interesting stratigraphical 
phenomena. It has at the base a layer of conglomerate about 
2%’ thick. The conglomerate is composed of small argilla- 
ceous and silicious pebbles, and is not very coherent. Something 
like two feet of sandstone rest upon the conglomerate; the 
