824 The Original Chazij Backs — Brainerd and SeeJij. 
limestoues are well marked by their lithological characters and 
by their fossils; and some of them appear eastward in western 
Vermont in even greater force than at Chazy. 
The economical importance of these rocks was shown by the 
discovery, about twelve years ago, of Chazy fossils in West 
Rutland, Vt., proving that the famous white and blue marbles 
of this region belong, at least in part, to this formation. But 
other beautiful marbles are also Chazy; "the Lepanto," avariet}"^ 
with reddish spots, quarried south of Plattsburg, N. Y.. the 
"French Grrey," from Isle la Motte, and the black marble so 
generally used for tiling, come from various strata of this for- 
mation. Large quantities of the purest lime are made from 
this rock in various towns of western Vermont — Swanton, 
Winooski and Whiting. Its massive beds have also furnished 
for many years excellent building material for forts, bridges 
and locks of canals. 
As preliminary to a study of this formation in western 
Vermont, we present in this article a detailed account of its 
appearance in Chazy, N. Y., where it was first named and 
studied by professors Hall and Emmons nearly fifty years ago. 
For convenience of reference and for a better understanding 
of the accompanying map, we give below in a condensed tabular 
form, the results of our measurements. 
Measuremehts at Chazy in A-Sceistding Order. 
Grouii A. 
FEET 
1. Iron-grey, fine grained dolomitic limestone, in beds one or two feet in thick- 
ness, weathering drab with fine yellowish streaks at right angles to plane 
of bedding; containing Orthis costalis and crinoidal fragments 110 
2. Tolerably fine limestone, filled with fragments of erinoids, containing Ortbis 
and Strophomena 20 
3. Measures concealed ^ 40 
4. Impure limestone, filled at bottom with Orthis, thin-bedded when long ex- 
posed to weather, the upper six feet abounding in crinoidal fragments 30 
5. Fine grained, massive limestone containing Scalites angalatus, Raphistoma 
and fragments of trilobites 25 
6. Impure limestone, abounding in Ortbis 10 
7. Measures concealed 25 
8. Massive, grey limestone, largely made up of crinoidal remains, having red 
spots in a stratum about 10 feet from the top; abounding near the middle 
of the strata with gasteropods. Bellerophou, Raphistoma, Metoptoma, 
Asapbus marginalis, Stenopora fibrosa, Bolboporiles americauus, Rete- 
pora gracilis 50 
aroup B. 310 
1. Thick bedded, nodular, dark colored limestone, containing Muclurea magna 50 
2. Massive, pure limestone, grey, fine grained, often oolitic, abounding in crinoi- 
dal remains and titeuopora Qbrosa 20 
3. Massive, bluish black, tolerably pure, nodular limestone, containing Ma- 
clurea magna and masses of blackchert 45 
