Y44 The American Geologist. April, 1892 
The accompanying diagram, Fig. 1, represents a cross section 
of the coral, the outer wall, where wanting, being indicated by 
the dotted line. The fragment found is 6 mm. in diameter, Fig. 
2 represents a longitudinal section of the inner poriferous 
structure. 
This form bears a close resemblance to Ethmophyllum whitney?, 
Meek,* except that the radiating septa meet the outer wall ata 
much less distance than in the figured specimens of this species. 
The number of septa is about the same, being at least 36. Some 
Fie. 1 is drawn twice the diameter. 
Fic. 2 is about five times as large as: 
as original section. 
doubt is entertained as to the exact equivalency of the number by 
reason of the partial loss of the outer wall and some of the septa 
in the specimen, 
The pebbles of chert from the osseous conglomerate at Gay 
Head show less clearly their organic contents, but coralline strue- 
ture has been detected in a number of pebbles. Those contain- 
ing fossils are of dark blue, almost black chert, are more or less 
rounded, smoothened and polished, and range in :diameter from 
half an inch to pieces two or three times this size. 
Occurrence of the Pebbles: These fossiliferous pebbles have so 
far been found by me only in the Neocene beds carrying the 
remains of Cetacez and sharks, and in the base of the overlying 
ereensand in the places where the osseous conglomerate was par- 
tially or wholly reorganized in the deposition of the greensand, 
At Gay Head, the osseous conglomerate is on the average about 
one foot thick, but in West Tisbury it attains a thickness 
of at least two, and in some places, three feet, being apparently 
the fossiliferous upper portion of the white sands and clays which 
were deposited upon the plant-bearing Cretaceous beds described 
by Mr. C. D. White.t The number of these chert pebbles in the 
Neocene gravel beds is relatively small, the mass of the deposit 
being composed of quartz of vein origin. In the Gay Head sec- 
*C. D. Walcott: 10th Annual Rept. U. 8. G.S., p. 601, pl. LV. 
+On Cretaceous Plants from Martha’s Vineyard, Am. Jour. Sed., (IIT) 
XXXTX, 1890, pp. 93-101. 
