APPENDIX. 309 



zontally imbedded, projecting their roots and trunks in a striking 

 manner above the water. These trees, on inspection, are merely 

 preserved, not petrified. They appear to have been exposed to 

 view, in modern times, by the wearing away of the bank. Cer- 

 tainly, none of the old travellers mention them. 



The mode of this formation may be clearly seen. Winds, at 

 some ancient period, have been the agent of blowing the sands, 

 as they were washed up by the lake, and redepositing them on 

 part of a prostrated forest, resting directly on the clay stratum. 

 The trees, thus buried in dry sand, have been preserved. In 

 process of time, the river encroached upon these antique beds, 

 exposing them to view. There are also antique fresh- water shells 

 found in similar positions near this spot. No rock is, thus far, 

 found in sitCc in ascending the lakes. The old surface of the 

 country is wholly of diluvial formation, except where it shows 

 lake action. 



Huron Coast from Fort Gratiot to Michilimackinac. — 

 About two hundred and thirty miles lie stretched out between 

 these two points. Lake Huron charms the eye, with the view of 

 its freshness and oceanic expanse. But the entrance is without 

 rock scenery, and the student of its geology must be a patient 

 gleaner along its shores. Long coasts of sand and gravel extend 

 before the eye, and they are surmounted, at a moderate elevation, 

 with a dense foliage, which limits the view of its structure to a 

 narrow line. Portions of this coast are heavily loaded with the 

 primitive debris* from the North. These are found, in some 

 places, in heavy masses, but all are more or less abraded, showing 

 that they have been transported from their original beds. In 

 one of these, I observed crystals of staurotide. 



The first section of this coast reaches from Fort Gratiot to 

 Point aux Barques, a distance of about seventy -five miles. 

 Nearly midway lies the White Eock, a very large bqukler of 

 whitish-gray semi-crystalline limestone, lying off the shore about 

 half a mile, in water of about one and a half fathom's depth. It 

 is the effect of gulls lighting upon this rock, and not the in- 

 tensity of the color of the stone, that has originated the name — 



* In 1824, an Indian brought me a specimen of native silver found on this part 

 of the coast. It was imbedded in a boulder of mixed granite and steatite. 



