it was proposed to take soundings, and some could not be reached on account of the great number of vessels lying about the wharves; but it is confidently believed that a sufficient number have been taken to clearly and unmistakably indicate the depths of water and mud and the character of the bottom.

As will be seen by reference to the profiles, rock presents itself under the mud near the southern termination of the survey at Harrison street, and also at the northern termination near Chestnut street. The intermediate distance presents clay and sand; in some cases, the former, pure blue, and in others, a mixture of both; in either case of so tough a character as to demonstrate very conclusively its entire adaptation for a permanent foundation. The sounding rod was driven in every case to such a depth as to sustain a steady weight of nearly thirty-four tons.

A map of cross sections is also submitted, which indicates the soundings transversely with the water front. The depths of water on the four different lines, have reference to "mean low tide," as established by the United States Government Engineers, at the dock at Fort Point. To facilitate this work, and as useful in indicating the condition of the tides in the bay, I established a similar tide guage to that of the Government, at the foot of the boat stairs at the intersection of the water front line and the south line of the Jackson street wharf.

The accompanying table exhibits the stations, depth of water, depth of mud, (in feet,) and the character of the bottom along the four lines of soundings.

I have not considered myself called upon at this time to discuss the character of the sea wall or water front improvement, but deem it not out of place to again express the clear conviction in my own mind, of the perfect adaptation of the bottom of the bay, where soundings have been taken, for a permanent foundation for the proposed protection of the water front. Very respectfully,