96 PICTURESQUE SKETCHES 



But the cephalopodous inhabitants of the seas 

 during the carboniferous period were still the most 

 important and the most numerous of the molluscous 

 animals ; and they included not only the straight 

 shells of orthoceratites, but a large number of spirally 

 twisted species, bearing a somewhat different relation 

 to the nautilus. The most important are called 

 Goniatites* (fig. 40). The nature of the difference here 

 Fig. 40 exhibited, and its influence 



on the habits of the animal, 

 will be considered in a fu- 

 ture chapter, when speaking 

 of the Ammonites, fossils 

 of a yet newer period. 



It has been already men- 

 tioned that the fishes, which, 

 during the devonian pe- 

 GONIATITE. r i 0( j were f or the most part 



of small size, and could not have been extremely 

 formidable or powerful, were gradually advancing in 

 development towards the latter part of the period, 

 and that several new forms, of strange aspect and 

 gigantic size, were then introduced. These seem to 

 have attained their maximum of size and strength 

 during the carboniferous epoch. 



Two great natural families of fishes, one of them 

 entirely, and the other almost extinct, seem to have 

 occupied at this time the place of the great marine 

 reptiles which succeeded and displaced them. These 

 two families are nearly allied to each other, and pre- 



* Goniatitcs, jofWQ (gonos), an angle ; from the angular markings 

 made by the intersection of the walls of the chambers and the outer shell. 

 (See cut.) 



