50 T. G. HALLE, MESOZOIC DEPOSITS AND FLORAS OF PATAGONIA AND TIERRA DEL FUEGO. 
The region of Lago San Martin undoubtedly offers great possibilities for a study 
of the passage beds between the Jurassic and the Cretaceous. Though all the fossils 
hitherto described are considered to occur in Cretaceous strata, there are reasons to 
believe that the Jurassic is represented, too. The occurrence of both marine fossils 
and plant-bearing strata will no doubt make it possible not only to establish a 
palaeontological subdivision of the important »meseta series» but also to arrive at a 
better determination of the correlation of the flora. 
