62 



the old Lias seas until the close of the chalk period, more 

 than four hundred different species lived, all differing in size,, 

 and shape, and ornament. Many were from three to four feet 

 in diameter, while some were small as our smallest shells, 

 more or less ornamented, and from their attractive appear- 

 ance they have excited the attention of the learned and the 

 vulgar in all ages. The Ammonites are commonly known as 

 " Ram's horns," a form they very much resemble. The 

 vulgar term " Ram's horns" is just the same as the learned 

 term " Ammonites." The original term was comu ammonis> 

 so called from the fancied resemblance between this fossil and 

 the horn that sometimes ornamented the statue of Jupiter 

 Ammon, and the old term corntc ammonis is sometimes cor- 

 rupted into the term " Horn of Moses," and this again into 

 " Cornamoneys," by which the Ammonites are sometimes 

 known in the North of Ireland. Wherever we find this Chalk 

 or Lias in the North of Ireland these fossils may be found ; 

 indeed, wherever those beds are found in any part of the world, 

 there Ammonites are found. They have been found in the 

 Lias many thousand feet high on the Himalaya mountains, 

 and of the very same species as we get at Larne, Islandmagee, 

 or Ballintoy. All the Ammonites were chambered shells, very 

 like the well-known Nautilus ; indeed, the latter is a very near 

 relation of theirs, from which it differs chiefly in the character 

 of the partitions that divide the several chambers of which 

 the shell is composed ; in the Nautilus the partition is 

 plain, in the Ammonite it is foliated. Many other families 

 of chambered shells existed and became extinct long before 

 the first Ammonite. Some of its ancient relations lived 

 even before any of our coal fields were deposited. The 

 remains of them are found in our Carboniferous Lime- 

 stone, as, for example, the limestone of Castle Espie, in 

 the County Down, where monster shells are found from 

 four to six feet long. These shells are called Orthoceratites. 

 The term " Orthoceras " is simply " straight horn," and the 



