Chasmosaurus -described by Lambe, 1914 (Dodson, 1996). It is known as the "Chasm lizard". It has enormous fenestrae, reducing half of the frill to a slender T-shaped framework. The horn cores are relatively small with only the postorbital horn cores preserved (Dodson, 1996). The squamosals, according to Dodson, 1996, "are like long isosceles triangles" that are very broad at the front and taper back, reaching almost to the edge of the parietal.