Correspondence—Prof. J. F. Blake. 45 
the ordinary type are seen in the new specimen; but I had to add 
‘“‘the body chamber and the last few septal chambers only [those 
which are distorted] being preserved in association.” This is now 
no longer true, but the remainder of my description was entirely 
based on the probability, not to say the certainty, of such a specimen 
being ultimately found. It runs, “The earlier septa are of the 
ordinary kind, with very little convexity and the siphuncle is ex- 
centric, in some of large size... The last few chambers are 
distorted and their dorsal portions are seldom seen.” These dorsal’ 
portions, as in the specimen figured by Barrande (Syst. Sil. de la 
Bohéme, vol. ii. p. 513), are well shown in the new specimen. I 
arrived at the same conclusion as Professor Lindstrom—that the 
Ascoceras ‘‘is by no means the simplest form of Cephalopod, but 
the most abnormal,” and included it with Poterioceras and others in 
the group Inflati, the genus being characterized by having its 
“later septa distorted.” The group is said to diverge from the 
Conici, i.e. the Orthocerata, etc., and to be remarkable for the loss 
of the early septa. 
It is satisfactory that in all these points the new specimens from 
Gothland confirm the previous observations. J. F. Buaxn. 
THE MONIAN SYSTEM. 
Sir,—I feel greatly indebted to Dr. Callaway for introducing the 
Monian System to the notice of your readers. It was through his 
advice I went to Anglesey, and he naturally takes a fatherly interest 
in the result. 
There are, however, certain points in his “‘ Notes” which call for 
explanation or reply. 
1. I am happy to recognize that Dr. Callaway, in 1887, quite 
independently of my observations, came to the conclusion that the 
hornblende-schists were of igneous origin, notwithstanding that such 
a conclusion entirely overthrew his reading of the succession in the 
‘“‘oneissic series.” I must even confess that he is bolder than I am, 
for my statement that these schists are igneous, is made in fear and 
trembling; for though I am forced to it by the stratigraphy, I know 
it would have been laughed at a few years ago. Nor can I get as far 
as ‘foliated felsites,” those so considered by Dr. Callaway being 
compressed and indurated examples of the ordinary mica-schists of 
the district. 
2. As to Parys Mountain, there are two other writers’ opinions to 
consider besides Dr. Callaway’s. 
38. As to the Llanfechell Grit. I acknowledge it would be of 
some importance if it could be shown that any large part of the upper 
portion of the series was made up of fragments of the lower ; but after 
all the Llanfechell Grits are merely subordinate bands in a long series, 
and there are no conglomerates in association with them, so that 
at best any included fragments would be poor evidence. Moreover, 
it seems quite common in these old rocks, for the earlier deposits 
to be rapidly altered and to contribute to the later. Thus the con- 
