520 The American Naturalist. [June, 
Warp, D. J. H.--What is God? Dover, 1896. From the author. 
WHITE, C. A.—Memoir of George Engelmann, M. D., 1809-1884. Extr. 
Biog. Mem. Natl. Acad., Vol. IV, 1896. From the author 
WIELAND, G. R.—Archelon ischyros: A new gigantic Cryptodire Testudinate 
from the Fort Pierre Cretaceous of South Dakota. Extr. Amer. Journ. Sci., 
Vol. I, 1896. From the author. 
General Notes. 
PETROGRAPHY. 
Mud Enclosures in Triassic Trap of New England.— 
Emerson,’ in an interesting and well illustrated paper, gives an account 
of tuff deposits at Granby and Holyoke, Mass., and of a sandstone con- 
taining fragments of a diabase very rich in feldspar existing a few feet 
above the Holyoke trap sheet in the valley between Tom and Little 
Mountains. At Dibbles and at other places the normal ‘trap’ of the 
region is filled with enclosures of a calcareous mud, which are so related 
to the enclosing rock as to leave no doubt that the mud was forced into 
the trap before solidification took place. In its advance the rolling lava 
sheet carried some of the mud beneath it, so that it now contains a muddy 
lower layer as well as a muddy upper layer. In places, especially near 
Greenfield, Mass., the trap, which is mainly a diabase, solidified as 
pitchstone, as a result probably of the action of the steam generated by 
the heating of the lower mud stratum. In these places the lower por- 
tion of the sheet is a mixture of sand, fragments of sandstone, frag- 
ments of diabase and of pitchstone, all cemented together by glass, 
which is cracked and shattered. In the crevices thus formed albite, 
diopside and other minerals have been deposited. Elsewhere, sand- 
stones and diabase glass, trap and breccia are intermixed in great con- 
fusion. The petrographical description of all the types of breccia and 
pitchstones are faithfully given by the author. The glasses in the glass 
breccia of Meriden, analyzed by Stokes, is composed as follows: 
SiO, TiO} CO, P,0; F Al0O3 FeO; FeO MnO a CaO MgO K,O NaO H,O Total 
2.19 15 tr 13.96 5.23 467 tr .08 9.42 7.69 2.02 1.85 4,72 — 99.92 
The lava sheet is supposed to have moved over the bottom of a water 
basin blending with the mud and sand with which this bottom was cov- 
ered. The mud was drawn up into the liquid lava by currents, an nd 
the great amount of water thus introduced caused it to solidify locally 
1 Edited by Dr. W. S. Bayley, rane agen an Waterville, Me. 
? Bull. Geol. Soc. Amer., Vol. 8, p 
