U. S. B, F.— Doc. 890. 



PLATE XVII. 



FIG. 1.— LOWERING THE DREDGE. 

 (Photofrom Prof.E. N. Cory, Maryland State University.) 



FIG. 2.— EMPTYING THE DREDGE. 



In ttiis case tiie dredge has been lifted by a doni<ey engine, part of wiiicti may be seen at the right. 

 (Photofrom Prof. E. N. Cory, Maryland State University.) 



