Such deposits accumulate as depositional aprons that flank the scarps (steep slopes) bounding shallow-water platformal areas such as the modern Great Bahama and Little Bahama banks off Florida in the southeastern United States.
These deposits indicate a depositional environment of rivers draining into freshwater lakes in a generally arid or semiarid region, which from paleomagnetic evidence appears to have been located about 20° north of the paleoequator.
There are two principal types of epiclastic conglomerates and breccias: intraformational, derived penecontemporaneously by eroding, transporting, and depositing material from within the depositional basin itself; and extraformational, derived from source rocks that lie outside the area in which the deposit occurs.
Analysis of grain-size distribution is conducted with the disputed assumption that particular transporting agents and depositional settings (e.g., river delta deposits versus shallow marine longshore-bar sands) impose a distinctive textural "fingerprint" on the sediments they produce.
Combinations of these features are widespread wherever arid and humid conditions have alternated, and either category may merge laterally with the complex suite of erosional and depositional landforms generated by continental glaciers at higher latitudes.
Structurally, the depression that it occupies is continuous with that of the North China Plain to the southwest, but, topographically, the Liaoning plains are erosional rather than depositional in character.
Extraformational conglomerates and breccias, the coarse clastic sedimentary rocks derived by the weathering of preexisting rocks outside the depositional basin, are most important from the points of view of both volume and geologic significance.
Yet another scheme differentiates individual conglomerates and breccias according to depositional agency and environmental setting (alluvial fan conglomerate as opposed to beach conglomerate).
Depositional cycles similar to those of eastern North America can be recognized in Europe, but distribution of those sediments is confined to small isolated basins instead of a broad cratonic shelf.
Oceanic troughs continued to receive clastic facies, particularly turbidites (sedimentary rock formed by a turbidity current), and pulses of mountain-building began to markedly affect the depositional sequences and their thicknesses.
