Dip/ii/p/iylluin SimcoCnse {Bill) Iio)n. — iSherzer. 93 
where it approached a quartz vein. Both fresh and decomposed por- 
tions luid the same orientation, and it is possible that the clear portion 
may have heen an enlarj^euient of the original grain. 
In order to asrertain the character of the rocl< arountl the edge of the 
"kernds" where a transition between the two varieties might be look- 
ed for, two sections were cut from a small hand specimen one-half of 
which consisted of a portion of a "Aenie-r' and the other of the usual 
grey granite. The granite near the "kernel" was found to resemble 
the ordinary granite in containing a t:on3i<Iera))le amount of pyrite, 
though less than the more altered granite usually holds, as well as in 
the fact that all the hornblende and ejjidote and practically all the 
chlorite has disappeared. A number of oblong forms were also to be 
seen, being of the same shape as those descriljed in the sections of the 
"kernels" as probably decomposition products of hornblende. This 
rock however shows these in a still further stage of alteration, being 
now composed of an aggregate of calcite grains, often with a little py- 
rite and iron ore. The rock also contains some quartz, a portion of 
which occupies corners and is more or less broken and probably a pri- 
mary constituent, while the rest occurs in a few irregular-shaped ag- 
gregations associated with calcite and pyrite in crushed portions of 
the rock and is secondary. The rock near the edge of the "kernels" 
therefore may be said to be intermediate in character between that of 
the "kernels" and the ordinary granite, but to resemble the latter more 
closely than that of the former. It is probable that some of the calcite 
masses found in the ordinary granite may be remains of the horn- 
blende originally present but which have now to a certain extent lost 
their original shape owing to movements in the rook. It may therefore 
be stated that the ore of the Treadwell mine is a granite, probably be- 
longing to the class of the hornblende granites, much crushed, altered 
and impregnated with secondary (juartz, calcite and pyrite ; that the 
"kerneh" are portions of the rock in which alteration is less complete 
than in the mass of the granite and that at least a considerable portion 
of the gold present in the ore is contained in the pyrite as free gold. 
NEW CHARACTERS OF DIPHYPHYLLUM SIMCOENSE 
(BILL.) ROM. 
By Will II. Sherzer. 
The following description of a coral, found in the Ann Arbor 
drift, may possess interest for students of paleontology. It 
consists of a colony of cylindrical, somewhat flexuous polyp 
stems, connected by scanty, lateral processes, similar to those 
in Eridophyllum, placed at irregular distances. Increase is 
seemingly by lateral gemmation. The epitheca is thin, show- 
ing plainly the longitudinal striations, which average about 
three to the millimeter. Transverse wrinkles of growth encir- 
cle the stems, from two to five in the space of one millimeter, 
