298 The American Geologist. NovembeiMooi, 
two miles south of Lockport on the Erie canal. His explana- 
tion was that the mass was the result of mineralization. The 
encrinal band may be traced into western Monroe county 
before its characteristics entirely fade. No search for reefs 
has been made in this quarter as yet, and the cursory examina- 
tion given the oiUcrops between here and Niagara gorge has 
failed to reveal others. 
Two of the masses west of Lockport have been known to 
the writer several years, but their nature was not clear until 
they were obsers^ed at Niagara gorge in connection with the 
reef structures of the Clinton. 
Bryozoans form the main constructional element of these 
old reefs. One of them exposed in the quarry on the eastern 
bank of the Niagara, a short distance south of the third watch- 
man's hut, is forty-five feet long and nearly a solid mass of 
fistuliporids. Crinoids are nearly or quite as important in some 
cases as the Bryozoa. The favositc and hclioUtc corals are 
sometimes important builders. 
The peculiar groupings of special forms are as marked a 
feature here as in the reefs of the Clinton. Some of them are 
remarkable for their general assemblages, but in most ftases at 
various stages in the growth, or at various points upon these 
masses and occasionally throughout their entire formation, cer- 
tain forms predominate or occur in unusual numbers. Some- 
times they are corals, delicate branching bryozoans, trilobites 
or cephalopods. 
It is noticeable that a number of species, mainly brachio- 
pods and trilobites, common in the Clinton reefs, nearly one 
hundred feet lower, are found here. 
These masses in the Lockport limestone of western New 
York find their counterpart in lithological character, fossil con- 
tents and stratigraphic position, in the reefs described by Dr. 
Chamberlin* in the Waukesha and Racine beds of the Wiscon- 
sin Niagara. These structures were found toi fomi a barrier 
reef sixty miles in length. From them two- hundred species 
have been obtained. 
Dr. Chamberlin calls attention to a feature which we have 
already noted in the reefs of New York, viz. a tendency of the 
life of the period to collect in groups of special formsi, which 
*GeoL of Wis., vol. i, 1873-1879, pp. 183-18G; and Geo/, of Wis., vol. ii, 
(1873-1877), pp. 369-71. 
