380 SIR WM. E. LOGAN'S VIEWS. 



which might be taken as representing two distinct layers. If they are such, they are comprehended in a 

 thickness of about 150 feet; but the circumstances of the case, connected with the physical structure, make 

 it probable that the one band is a repetition of the other through the influence of an anticlinal fold or a 

 dislocation. Both out-crops dip to the southeastward. 



From the more northern out-crop which we shall call (A 2 ) we have obtained Orthis \,Leptcma 1, Camer- 

 ella 1 Lingula 2, Discina 1, Agnostus 3, Conocephalitcs 1, Arionellus 4, Dilcellocephalus 6, Bathyurus 4. 

 From the more southern out-crop (which we shall call A 3 ) we have Dictyonema 1, Orthis 2, Leptcena 1, 

 Strophomena 1, Camerella 1, Cyrtodonta (?) 1, Murchisonia 3, Pleurotomaria 7, Helicotoma 2, Strapa- 

 rollus 2 Capulus 2, Agnostus 1, Bathyurus 4, Gheirurus 2, Amphion 2. From a third out-crop, which is 

 still further southward, and supposed to be another repetition of the same band (which we shall call A 4 ), 

 we have Orthis 1, Camerella 1, Asaphus (A. Illwnoides) 1, Bathyurus 1. Tracing A 2 or A 3 round the 

 extremity of a synclinal, and finding occasional indications of -the fossils of. A 2 and A 3 , we arrive at a posi- 

 tion on the south side of the synclinal. We shall call the position P. Here the band A 2 or A 3 euds, but 

 a bed of sandstone a little above it is traceable over an anticlinal to a junction with a conglomerate band 

 lower than A 2 or A", showing that A 2 or A 3 must merge into it. .Call this A 1 . In this we have Asaphus 

 (A. Illainoides) 1, Menocephalus (M. globosus) 1. These two species occur in the same fragment of rock. 

 Of all these fossils, 1 Orthis is common to A 2 , A 3 and A 4 ; 1 Leptcena, 1 Camerella, 1 Lingula, 1 Agnostus, 

 and 1 Bathyurus, are common to A 2 and A 3 ; 1 Asaphus is common to A 3 and A 1 . 



The dip at P is to the southeastward, and therefore an inverted dip. Northwest of this, and therefore 

 above it, at such a distance as would give a thickness of between 200 or 300 feet, we have a band of shales 

 with nodules of limestone, the nodules made up of other rounded masses in a matrix holding fossils, 

 many of them silicified. From a few of these compound nodules we have obtained Orthis 11, 

 Leptcena 1; this band we shall call B 1 . -A band like this occurs about half a mile or more to the south- 

 westward. It may be a higher band, or it may be the same band, but we shall call it B 2 . From this we 

 obtain Crinoidcea (columns) 3, Orthis 1, Camerella 1, Nautilus 1, OrtJioceras 1, Leperditia 1, Trilobites 

 (2 genera undetermined) 2. In another position to the southeast, on the southeast of the same anticlinal 

 previously mentioned, we meet with a conglomerate band supposed to be the same as B 3 ; but, in case it 

 should be different, we shall call it B 3 . Here we have Orthis 3, Pleurotomaria 2, Murchisonia 1, Ophi- 

 leta 1, Helicotoma 1, Nautilus 1, Maclurea 1, Orthoceras 3 or 4, Cyrtoceras 1, Bathyurus 1, Illa>nus 2, 

 Asaphus 1. Of all these fossils, 1 Orthis and 1 Camerella are common to B 1 and B 3 , the same Orthis and 

 Camerella with 1 Leptcena are common to B 1 , A*, A 3 and A 2 . 



To the north of all these exposures, and on the northwest side of a synclinal running parallel with the 

 synclinal already mentioned, fossils have been obtained in a cliff of about 100 feet, composed of limestone 

 conglomerate, thin-bedded limestones and shales. Their equivalence is not yet quite certain, but the strata 

 are supposed to be not far removed from A 1 and A 2 . We shall call this cliff A. The fossils from it are 

 Tetradium 1, Orthis 1, Lingula 2, Trilobites (genus undescribed) 1, with a great collection of compound 

 Graptolidce, described and being described by Mr. Hall under the genera Graptolithus 25, Eetiolites 1, Eeteo- 

 graptus 2, Phyllograptus 5, Dendrograptus 3, Thamnograptus 3, Dictyonema 3. 



I have given you these details of localities, because as the subject requires further investigation we do 

 not yet wish to commit ourselves entirely as to the equivalency of separate exposures. But there is no 

 doubt that the whole is one group of strata deposited under one set of alternating circumstances. The 

 whole fauna, as known up to the present time, is composed of 



Articulata, .36 species. 



Mollusca, ; . . 55 " 



Graptoiidfe, 42 " 



Radiata, . . . v 4 " 



137 



Of this fauna not one species is found in the Anticosti group, where we have a gradual passage from the 

 fauna of the Hudson River formation to that of the Clinton, and not one of any formation higher than the 



