Glacial till is the simply the unsorted sediment and rock fragments carried by a glacier. Till can contain everything from clay-size material all the way to boulder size material. Large till deposits are found throughout the in the northern Midwest and northeast U.S. and Canada due to the deposits from continental glaciation. It is also found in mountainous areas, e.g., the Rocky Mountains due to alpine glaciation.
Till is generated at the base of the glacier and there is often a pile of rock debris pushed in front of the glacier called a terminal morraine. It can also be found as a ridge of material along the sides of a glacier (lateral morraine) and where two glaciers meet and their lateral morraines become a medial morraine. Till is recognizable by the highly unsorted nature of the sediment and angular rock fragments, See the attached photo: Till is distinguished from water lain deposits because water tends to sort the sediment.