The Collaborative International Dictionary of English v.0.48:

Mesotype \Mes"o*type\, n. [Meso- + -type: cf. F. m['e]sotype.]
   (Min.)
   An old term covering natrolite or soda mesolite, scolecite or
   lime mesotype, and mesolite or lime-soda mesotype.
   [1913 Webster]