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CO. Davies Sherborn—Concentric Structure in Limestone. 255 
I1J.—On «a Limestone with Concentric Structure Frrom Kuuwv, 
Nort Inpta. 
By C. Davres SHerzorn, F.G.S. 
N the Thirty-Sixth Annual Report on the New York State Museum 
of Natural History (Svo. Albany, 1884), is a folding plate 
with a fly-leaf descriptive of a specimen with peculiar structure from 
the Calciferous Sandstone group of Greenfield, Saratoga Co. It is 
referred to anew genus and species under the name of Cryptozoon 
proliferum,' but no author’s name appeared to either the plate or 
the description.*?- The peculiar appearance of the American figure 
reminded Prof. Rupert Jones of a specimen in his collection, and 
having kindly placed it in my hands and permitted me to bring it 
before the notice of the readers of the GronogrcaL MaGazine, he 
has given it to the British Museum. Prof. Jones’s specimen was 
collected by the late John Calvert, F.G.S., the author of “ Vazeeri 
Rupi, the Silver Country of the Vazeers in Kulu,” * and the rock 
is referred to at p. 8 of that book. The specimen was shown by 
Mr. Calvert to Sir Warington W. Smyth (whose opinion as to its 
inorganic nature is quoted by Mr. Calvert), and afterwards given to 
Prof. Jones. At first sight it very much resembles the figures of 
the American fossil. It consists of an oblong slab, 4 x 24 x 1 ins., 
showing in its centre a round or rather oval concretion, the matrix 
being dark slate-coloured limestone, similar in general appearance to 
our Carboniferous Limestone. One face of the slab has been cut 
through the centre of the round mass and the other face half-way 
between the centre and the periphery. The concentric structure 
occupying nearly the whole of the surface of the slab (as may be 
seen in the accompanying Figure) touches one side; and only the 
corners of the slab show the undisturbed bluish matrix. The rings 
are of many shades of grey, with a few of an orange-pink colour 
passing into brown. On two sides of the face of the slab are indi- 
cations of other concentric masses, and with one of these the example 
in question appears to have been joined, as it shows a tendency to 
assume a pear shape, with a “point below” the root or starting- 
point of growth—as in the description of the figures of the American 
form. 
It seems certain that the American specimens are of organic origin, 
for we are told that “the substance between the concentric lines in 
well-preserved specimens is traversed by numerous, minute, irregu- 
lar canaliculi, which branch and anastomose without regularity,” 
and that “the central portions of the [concentric] masses are usually 
filled with crystalline, granular, and oolitic material, and many 
specimens show the intrusion of these extraneous and inorganic 
substances between the concentric Jaminz.” In the Indian specimen 
1 Since this paper was written and handed in to the Grou. Maa. another note on 
Cryptozoon has been published in the 14th Ann. Rep. Geol. N.H. Survey, Minnesota, 
for 1885, 8vo. St. Paul, 1886. 
2 The authorship of this paper has been referred to Dr. James Hall, of Albany. 
3 8vo. London and New York, 1873. 
