312 Maclure on Geology. 
What Werner calls primitive trap may perhaps be compact 
hornblende, or perhaps the newest fleetz trap, when it happens 
to cover the primitive ; for, this species of trap, like the cur- 
rents of lava, covers indiscriminately all classes of rocks, and this 
is one reason why | consider it as the remains of ancient lava: 
Transition trap is a rock that I have not met with; it may 
perhaps be a part of the fleetz trap that happened to cover the 
transition, without any immediate connexion, but like a cur 
rent of lava, overlying all the classes of rocks it meets with. 
This misapplication of names naturally arises from the system 
of Neptunian origin, on which the nomenclature of Werner is 
founded. 
Greywake and greywake slate are aggregates of rounded pat- 
ticles of rocks, evidently the detritus of more ancient forma- 
tions, and differ from the aggregates of pudding and sandstone of 
the secondary class, in the following properties, viz. 
The aggregates of transition are harder and much more comr 
pact than the secondary; they are also cemented by argil, taking 
a slaty form. 
ment is in much greater quantity, in proportion 
is ce 
Bg a ES ae 
ee to the 
partic es cemented, and has the appearance as if the cement at 
the time of formation, had consistence sufficient to prevent the 
particles from touching each other. : 
_ They have in common with all the transition rocks, a regt 
lar and uniform dip from the horizon, from 10 to 40 degrees 
and sometimes more. This is perhaps the strongest mark of 
distinction which separates them from the secondary, which are 
horizontal, or follow the inequalities of the surface 0? which 
they were deposited. 
The transition are distinguished from the primitive in being 
aggregates of rounded particles, having little or no crystalliza- 
tion, and containing,-or alternating with strata which contalp s 
ganic matter. ; 
The oldest red sandstone, with all its accompanying strata, 
I should incline to put into the transition, as having mary of the 
properties of that class, and occupying the same relative situa 
tion in the stratification of the globe. It is’ at a constant dip 
