Foerste.] 
262 
[May 1, 
the Massachusetts specimens under a new specific name, Hyolithes 
incequilateralis sp. nov., and make the larger specimens found at 
Nahant the type of this species. The limestones of Nahant are re- 
peated in a series of red slates northeast of Mill Cove in North 
Weymouth, as probably suggested by Prof. James Hall in his Pal. 
N. Y., Vol. hi, and certainly very definitely stated by Prof. W. O. 
Crosby in his Geology of Eastern Massachusetts. The strike here 
is N. 57 W. and the dip is 70° south. The strike at the Paradoxides 
Quarry towards the west across the river is about east and west, 
and the dip is also south so that the red slates and included lime- 
stones of Mill Cove probably dip under those of the Paradoxides 
Quarry. The Paradoxides of the Braintree Quarry all lie on their 
backs in the argillite as tilted at the present time. Observations 
on the larger forms of this genus elsewhere agree pretty well that 
this is a common method of occurrence of these trilobites. We are 
therefore of the opinion that the Paradoxides slates are not a part 
of an overturn fold, but indicate by their present position what was 
the former succession of the beds now forming the quarry. With 
this as a guide it becomes probable that the red slates and included 
limestones underlie the Braintree Paradoxides beds stratigraphi- 
cally. Since, however, the character of the limestones from Mill 
Cove identifies these red slates with the metamorphosed Nahant 
beds, and the Hyolithes found there is known to be a form belonging 
to the Olenellus Cambrian, the conclusion is that the red slates of 
Mill Cove are also of Olenellus Cambrian age, and that the Olenel- 
lus Cambrian underlies the Paradoxides Cambrian in Massachu- 
setts. The general strike of the limestones at Nahant is N. 50 E. 
and the dip is about 45° toward the N. W. The nearest slates 
probably of Paradoxides Cambrian age are in Malden where they 
have a northerly dip and a strike varying from N.E. to E. and W. 
The general indication would be that the Nahant beds pass be- 
neath the Malden slates but the exposures are too distant to make 
this observation of value. It is not likely the Olenellus Cambrian 
beds will be found near the coast of Massachusetts except in the 
regions mentioned, these rocks probably lying beneath the slates 
exposed in the harbor. That the slates of Boston harbor are of Para- 
doxides Cambrian age seems probable from the reported finding of 
Paradoxides in the drift of George’s Island. 
The Mill Cove slates are 12.5 miles distant from Nahant, and 
27.5 miles from Locality I, North Attleboro ; the distance from Na- 
