Examples from the Web for fragmental
These are overlaid by a series of alternating beds of crystalline (c) and fragmental (t) igneous rocks.
Fragmental rocks are often quite indurated—the matrix being as hard as the included stones.
Hence the form or outline of many of these fragmental craters is crescent-shaped.Volcanoes: Past and Present|Edward Hull
But the walls were admitting a fragmental echo of what must have been a reverberating voice.The Finding of Haldgren|Charles Willard Diffin
The rocks, so far as I saw them, are massive lavas, and not fragmental scori or other products of explosive eruptions.Mount Rainier|Various