246 Cincinnati Society of Natural History. 
‘“ the occurrence of such corals in the Miocene of Texas is well 
known.’’ He had further consulted his colleague, Dr. T. W. 
VAUGHAN, who said that it “‘may be an Acroporid coral, but 
too poorly preserved for definite determination’’ Fig. 1 
shows photograph of one of these fragments, enlarged 8 diam. 
Fic. 1. 
The pellets in a subsequent chemical analysis (see below) 
were shown also to contain calcium sulfate and strontium sul- 
fate in weighable quantities. They have evidently been 
formed around fragments of the coral as a nucleus, investing 
such fragments with concentric layers of barium (calcium 
and strontium ) sulfate. 
Dr. Ulrich, in his communication, suggests that “the sulfate 
of barium covering may be a metasomatic replacement of a 
similar original calcium carbonate investment. Such a 
replacement may, as in this case, extend to and include the 
nucleus.”’ 
As to the structure of the pellets, a transverse section reveals 
tubes radiating from the nucleus like spokes of a wheel (see 
Figs. 2-4), imbedded in a series of two or three incrusting 
concentric shells, surrounded by a series of cortical layers, 
into which the radiating tubes do not extend, though some 
radiated structure is discernible in the microscopic section of 
these cortical layers also. It seems that after the deposition 
of the inner shells, the process was interrupted, and the outer 
shells were formed at a later period. 
The inner layers are of a bluish white tint and quite com- 
pact; the cortical layers are creamy white and of less compact 
2 
