left till the last. The initial tendency to synclinal ridges was
obviated in places by the weakness of the rocks situated in the
synclines, but even then the tendency to retain elevation is apt to
cause low ridges. The drainage of the belt as a whole is anticlinal to
a marked degree, for the three main synclinal lines are lines of great
elevation, and the anticlines are invariably valleys.

In order of solubility the rocks of the Catoctin Belt, within the
limits of Loudoun County, to which section all subsequent geologic
data will be confined, stand as follows:

1. Newark limestone conglomerate; calcareous.

2. Newark sandstone and shale; calcareous and feldspathic.

3. Newark diabase; feldspathic.

4. Granite; feldspathic.

5. Loudoun formation; feldspathic.

6. Granite and schist; feldspathic.

7. Catoctin schist; epidotic and feldspathic.

8. Weverton sandstone; siliceous.

All of these formations are in places reduced to baselevel. The first
three invariably are, unless protected by a harder rock; the next
three usually are; the Catoctin schist only in small parts of its