Prof. W. H. Hobbs—The Charleston Earthquake, 1886. 197 
Fic. 8.—Lamna serra, A. S. Woodw. Lateral tooth, inner, (8a) outer, and (8%) 
lateral aspects. 
9.—Ditto. Lateral tooth, inner and (9a) lateral aspects. 
10.—Ditto. Anterior tooth, outer and (10a) lateral aspects. 
11.—Lamna appendiculata, Agass. Anterior tooth, outer and (11a) lateral 
aspects. 
” 12.—Ditto. Outer and (127) lateral aspects. 
Except Figs. 3, 44, 6a, allthe drawings are of the natural size. The original of 
Fig. 3 was obtained from the Province of Sergipe del Rey; all the other specimens 
from Maria Farinha, Province of Pernambuco. All specimens in the National 
Museum, Rio de Janeiro. 
be) 
ted 
39 
IJl.—Tuer Cuarteston Karrnaguakr or Aveust dlst, 1886, IN 
A New Lieut. 
By WituiAm Hersert Hosss, 
Professor of Geology in the University of Michigan, and Secretary to the Committee 
: of Seismology of the American Association tor the Advancement of Science. 
(WITH A MAP.) 
ITH few exceptions, surface dislocations within the earth’s crust 
or ‘earthquake-faults,’ have been described in connection with 
all earthquakes of large proportions.!. The Charleston earthquake of 
August 3lst, 1886, stands out in some contrast with most others in 
this particular, and it is further in contrast with some other earth- 
quakes for the reason that the phenomena recorded in connection with 
it have not as yet been brought into any relation with the structural 
geology of the district. A partial explanation of this may perhaps 
be found in the fact that the area most disturbed—the so-called 
‘epicentral tract ’—is entirely included within the coastal plain of 
the South-Eastern United States. Upon this plain the basement of 
rock is covered to very considerable depths by unconsolidated material, 
and it would perhaps be too much to expect that displacements upon 
fracture planes in the rock would be revealed in full measure at the 
surface. 
There is good reason to suppose that, in consequence of the easily 
adjustable nature of the coast deposits, considerable displacements 
upon fracture planes in the rock basement would at the surface of the 
ground be represented only by ‘ploughshare’ effects, opened fissures, 
and lines of ‘craterlets,’ the latter due to the rapid expulsion of 
water at points along the fissures. As shown by the extensive report 
of Major Dutton,’ all these phenomena appear to have been developed, 
thousands of fissures of variable but generally small dimensions having 
been opened throughout an area for about 600 square miles, while 
the craterlets were perhaps as large and as numerous as in the case of 
any other earthquake that has been described. It was further observed 
that the surface of the ground was in places thrown into a series of 
ridges and valleys, and that where these furrows cross the railway 
right-of-way the embankments exhibited changes of the same nature. 
! For a list of such dislocations formed in connection with the better known 
earthquakes, see Gerland’s ‘‘ Beitraege zur Geophysik,’’ vol. viii (1907), pp. 236-253. 
» C. E. Dutton, ‘* The Charleston Earthquake of August 31st, 1886’’: 9th Ann. 
Rep. U.S. Geol. Sury., 1890, pp. 203-528. 
