Haworth on the ArchcBan Geology of Missouri. 285 
are called Cambrian. All of my observations accord with these 
views with reference to the relative ages of the different rocks. 
There can be no doubt that the granites and porphyries are 
older than the sedimentary rocks, as the following considera- 
tions show : 
1° . Numerous instances were seen in which the stratified 
rocks overlie the massive ones and are non-conformable with 
their surface. Broadhead also describes and figures such con- 
tacts. 
2° . The stratified rocks in the whole country are nearly 
horizontal, rarely showing a dip of more than ten degrees. It 
is very probable that this would not be true had such large 
quantities of massive rock been forced up through them. 
3° . Nowhere has a contact zone of metamorphosed lime- 
stone or sandstone been observed. Had such large quantities of 
massive rocks been forced up through the stratified ones it is 
very probable contact metamorphism would be common. 
During Cambrian time this portion of Missouri existed as an 
archipelago of many small islands, some of which had deep, 
narrow valleys between, while others were mere peaks separated 
by five, ten, fifteen or more miles. Along these valleys the 
Cambrian rocks were deposited. 
(c). Relation of Dzassive rocks to each other. 
Long before Cambrian time, however, these islands had a 
history. They had been lifted above the ocean waters and 
subjected to different kinds of degradation. Along their shores 
and upon their hillsides deposits of their own material had been 
made which were subsequently firmly cemented together form- 
ing a breccia. The material of the cement is very like that of 
the fragments, so that it is often difficult or even impossible to 
distinguish between the two. At present this class of rocks 
must be almost entirely neglected, because the ascertained facts 
are too meagre to warrant a discussion of them. It is quite 
probable they have been given too prominent a place by those 
w^ho have written about them. 
So far as observed the granites are on comparatively low 
ground. Graniteville is in a valley, with high hills almost all 
around. The granite quarries at Syenite are on the banks of 
