Rocks formation

[crossword]

of or relating to rocks formed between the Triassic and Jurassic periods? 7 letters pattern R???T?C

[mylo74]

raustic?

[Deepdale]

Raustic is wrong, as the pattern is R?A?T?C. The "A" comes from 27 across "Camel Hair" Not sure what the answer is but, having tried all english lettering combinations, none of the dictionaries seem to have an answer either.

[Deepdale]

The correct answer is "Rhaetic"