Easton's 1897 Bible Dictionary:

Tarshish
   a Sanscrit or Aryan word, meaning "the sea coast." (1.) One of
   the "sons" of Javan (Gen. 10:4; 1 Chr. 1:7).

     (2.) The name of a place which first comes into notice in the
   days of Solomon. The question as to the locality of Tarshish has
   given rise to not a little discussion. Some think there was a
   Tarshish in the East, on the Indian coast, seeing that "ships of
   Tarshish" sailed from Eziongeber, on the Red Sea (1 Kings 9:26;
   22:48; 2 Chr. 9:21). Some, again, argue that Carthage was the
   place so named. There can be little doubt, however, that this is
   the name of a Phoenician port in Spain, between the two mouths
   of the Guadalquivir (the name given to the river by the Arabs,
   and meaning "the great wady" or water-course). It was founded by
   a Carthaginian colony, and was the farthest western harbour of
   Tyrian sailors. It was to this port Jonah's ship was about to
   sail from Joppa. It has well been styled "the Peru of Tyrian
   adventure;" it abounded in gold and silver mines.

     It appears that this name also is used without reference to
   any locality. "Ships of Tarshish" is an expression sometimes
   denoting simply ships intended for a long voyage (Isa. 23:1,
   14), ships of a large size (sea-going ships), whatever might be
   the port to which they sailed. Solomon's ships were so styled (1
   Kings 10:22; 22:49).


Hitchcock's Bible Names Dictionary (late 1800's):

Tarshish, contemplation; examination