525 
Reviews — Lyman's Geology of Japan. 
single section skowing tke geological relations of the formations, 
and this is the more stränge because it would appear tkat ample 
materials for rough ones at least have been collected. 
In connexion witb bis rock groups, our author, too, seems to 
place more importance than necessary upon tbe directions in wbicb 
tbe beds are folded, the folds of different regions, or of the same 
region with different axial directions, being tkought to mark different 
periods of disturbance, without the collateral testimony of uncon- 
formity or distinct Superposition, or mucb otber conclusive evidence 
being adduced to prove difference of age, eitber of tbe rocks tkem- 
selves, or in tbeir Systems of disturbance. 
The oldest group of the Island of Yesso is tbe Kamaikotan (or 
Home of the Gods) subdivision, a series of metamorpbic quartzites, 
talcose and quartzose scbists, blue marble, and blackish Serpentine, 
with greenish impure limestone, granites, and mica scbist. So far 
as we have gatbered, these rocks are all distinotly stratified, tbey 
contain no fossils, and are skarply contorted witb steep angles of 
dip from 45° to 60° or more. Tbey form tbe core of the island, and 
any mineral veins tbey contain traverse also rocks of tbe next newer 
stage, so tbat it is doubtful if tbey contain any peculiar to tkem- 
selves — even the gold of tbe superficial deposits not being excepted. 
These metamorpbic rocks are of unknown age. 
Next newer than this is tbe» Honimni group, containing very 
numerous, but for the most part tbin or impure beds of coal, witb 
some good coal, having but a small per-centage of asb, and some 
‘ furnishing ’ coke of good appearance. The rocks are ckiefly sand- 
stones of greenish or grey colour and grey sbales or clays. Tbe 
fossils found have been few, and not carefully studied; but the rocks 
are tkought to be of early Tertiary or possibly of late Secondary age. 
In probably tbe lowest beds a Ptychoceras and some Ammonites 
have been obtained. This group is more than double tbe tbickness 
of any otber. 
Conformably succeediug these, apparently, tbougb this is not dis- 
tinctly stated to be tbe case, is a group of Old Volcanic rocks, 
trackyte porpkyries, witb small crystals of glassy felspar, taken to be 
of late date, because of tbeir rkyolitic character. Light grey, coarse- 
grained Syenite occurs in tkem at several places, and diorite less 
frequently. These rocks, it is supposed, may have partly issued from 
volcanos tbat still send out new volcanic rocks. 
Tben comes tbe Toshibets group. possibly locally conformable and 
passing into tbat preceding. In this group Mr. Munroe distinguisbed 
two divisions, tbe upper of clays, sandstones and pumice, or otber 
conglomerates derived wholly from volcanic rocks, and tbe lower 
of shales, sandstones and conglomerates. Between tbe two be tbougbt 
at one place be detected an unconformity, tbougb there was none 
elsewbere. 
Derived pebbles of Syenite and otber crystalline rocks in these 
beds, supposed to have come from tbe Old Volcanic group, would at 
least suggest more of unconformity than is stated to exist. 
One bed, 500 feet or so from tbe top of the group, contains fossil 
