G. H. Kinahan — Irish and Canadian Rocks, (Jompared. 159 



Patella gi-aphica is fonnded on a single specimen. Should a 

 common specific name be required for this section of P. rugosa, it is 

 evident that F. tenuistriata, Deslong., must take precedence. 



EXPLAjSTATIOJST op plate IV. 

 Fig. 1. Fleurotomaria depressa, Phil. Oxford Clay, Scarborough. York 



Museum. Apical view. Flattened specimen. 

 „ 2. Fleurotomaria depressa, Phil. Kelloway Eock, Scarborough. Leck- 



enby Collection. Type of PL striata, Leckenby, bbfigurbd. 



Apical view. 2a. portion enlarged. 

 „ 3. Flenrotomaria guttata, PhU. Kelloway B-ock, Scarborough. Bean 



Collection, British Museum. Type of Fl. arenosa, Leckenby, 



REFiGURED. 3«. portiou enlarged. 

 „ 4. Fletirotomaria guttata, Phil. Kelloway Eock, Scarborough. Leck- 



enby Collection. Back view. 

 ,, 5. Fleurotomaria near to anglica, Sow. Dogger, Blue "Wyke. York 



Museum. 

 „ 6, 6«, 65.. Trochotoma calix, Phil. Dogger, Blue Wyke. Back, apical, and 



basal views. 

 J, 7. Fatella graphica. Leek. Kelloway Eock, Scarborough. Bean Coll. 



British Museum. Apical view. la. portion enlarged. 



{To be continued.) 



IV. — Canadian Aech^an or Pre-Oambrian Eooks and the Irish 



Metamorphic Kooks. 



By Gr. Henry Kinahan, M.E.I. A., etc. 



[Eead before the Eoyal Geological Society of Ireland.] 



S introductory to the subject of this paper, some observations 

 made in Ireland on foliation, or the structure induced by 

 nietamorphism, with other phenomena connected therewith, will be 

 submitted. 



Students of Petrology and Lithology seem now in general to allow 

 that there are three kinds of metamorphism, namely Eegional and 

 Contact, for which I have proposed respectively the terms Ifetapepsis 

 and Paroptesis,^ and Chemical change, to which King of Galway 

 gave the name Methylosis, while more recently the Americans called 

 it Paramorphosis. At the present time it is not intended to refer to 

 the latter, as these preliminary remarks refer specially to the others. 



In one and the same area Paroptesis or Contact metamorphism 

 must necessarily occur at a different time to Metapepsis or Eegional 

 metamorphism ; and the first may take place either before or after 

 the other ; or possibly there may have been two or more successive 

 actions which affected the rock or rocks of one area ; as, for instance, 

 first in places there may have been Paroptesis, while subsequently 

 these altered rocks were included in a Metapepsis area, while after- 

 wards in portions, or the whole of the area Paroptesis or Metapepsis 

 may again have taken place ; because, as long ago pointed out by 

 Lyell, vulcanicity often occurs over and over again, even with ages 

 between, in one place or one area. In places the present structure 

 of some of the Canadian Archseans would suggest that they were sub- 

 jected to a succession of periods of alteration, some due to Paroptesis, 

 others to Metapepsis ; to this subject we will hereafter return. 

 ^ Geology of Ireland, p. 175. 



