114 TAB WAS WAS, 
After the discussion of the conditions of preservation a comparison 
is made with some chert from Croydon, England. ‘The chert, instead 
of being composed of amorphous silica, was made up of “a dense 
aggregation of entangled spicules.” 
In classifying the spicules of course the classification of Zittel was 
followed. Representatives of the Monactinellids, ‘Vetractinellids, 
Lithistids (?) and Hexactinellids were found. Mr. Merrill introduces 
but few new names, contenting himself with describing and figuring 
the spicules the best that he could. | For eight of the forms figured he 
proposes names, recognizing however that later, several of the different 
spicules may be proved to belong to the same species. 
Of the various groups, the Tetractinellidz are the most abundant, 
and, strange to say, the dermal or flesh spicules are the most numerous, 
and are the best preserved. This is the reverse of what has been 
found by the students of the European cherts and flints. The writer 
of this review has found the same condition prevailing in the slides of 
the Texas flints that he has examined, as Mr. Merrill describes. The 
globo-stellates are the most abundant and best preserved. 
The following are the names proposed by Mr. Merrill: Geodia? 
Spint-curvata, Geodia ? cretacea, Geodia? austint, Geodia ? irregularis, 
Geodia ? tripunctata, Geodia ? texana, Geodia ? spint-pansata, Geodia ? 
hill. 
A single spicule of a doubtful Lithistid was found. The Hexactin- 
ellidze were but poorly represented. 
In discussing the process of formation of the nodules the theories 
advanced by Wallich and Sallas are first given. Then Mr. Merrill 
states that in the nodules studied by him the spicules were more per- 
fect in the body of the nodule than near the surface, those near the 
surface showing crushing and mechanical wear. ‘“‘The mechanical 
crushing differed considerably in the different specimens, and one 
showed complete obliteration of the spicular structure.” In the sponge 
spicules studied by Carter, Sallas and Hinde, all of which had been 
subjected to mechanical movement, the smaller spicules had been 
destroyed. Carter says that he did not find minute stellates or 
spines, or tubercles or the large spicules in the Haldon deposit. 
Sallas says that the once existing spicules are absent, because they 
have been dissolved. Hinde says that ‘flesh spicules are rarely met 
with in the fossil state.” In the Texas flints a scarcity of zone spicules 
and a great number of flesh spicules, preserved in the greatest perfec- 
