278 
GILBERT. 
represent sculpture districts and the direction of the fine 
parallel lines indicates the trend of the sculpture. The in¬ 
terspaces between shaded areas are largely occupied by maria 
and other plains on which no sculpture appears. 
The boldest carving is seen on the Apennines, the crest 
line of which is cut into battlements. From the hollows 
between battlements, rude grooves follow radially down the 
southern slope to its base. A similar sculpture appears on 
the Caucasus, but the range is traversed obliquely, from E. 
S. E. to W. N. W. The sculpture features of the Carpathians 
are less conspicuous, but immediately south of them is a 
tract occupied by drumlin-like hills, the axes of which point 
toward the Imbrian plain. The broad isthmus between the 
Mare Vaporum and the Mare Serenitatis is so thoroughly 
sculptured that most of its features exhibit parallel trend in 
a southwesterly direction. The great crater of Julius Caesar 
has lost most of its southern wall, and its valley is filled to 
the level of the remnant of rim on that side. Boscovich is 
barely to be recognized as a crater, and whatever other 
craters may have antedated the flood are defaced beyond 
recognition. Manilius, Menelaus, and a few others are of 
more recent date, and their clean cut features stand in strik¬ 
ing contrast to the general ruin. Similar features with 
slightly different trend characterize the plain for 200 miles 
south of Julius Csesar. The rims of Hipparchus, Albateg- 
nius, Ptolemy, and Alphonsus are all notched by grooves 
trending toward the Mare Imbrium, and some of these 
grooves can be traced to the vicinity of the crater Lalande. 
The rims of Parry, Bonpland, and Guerike, jutting island- 
wise from the Mare Nubium, are similarly notched, the 
trend here coinciding almost precisely with the meridian. 
Through the entire region lying between the Mare Nubium 
and the Maria Serenitatis and Tranquilitatis, sculpture and 
the associated veneering have so modified the surface that 
there is no difficulty in discriminating the craters of later 
date from those of earlier. The whole topography may be 
classified as antediluvial and postdiluvial. The only small 
