1. Upper Mantle: This is the layer directly beneath the Earth's crust. It extends from the base of the crust (around 30 km deep) to a depth of about 660 km. The upper mantle is further divided into:

* Lithosphere: This is the rigid, outermost layer of the Earth, composed of the crust and the uppermost part of the mantle. It is broken into tectonic plates that move on top of the asthenosphere.

* Asthenosphere: This is a partially molten, soft, and viscous layer below the lithosphere. It is characterized by its ability to flow slowly over long periods, making it the driving force for plate tectonics.

* Transition Zone: This is a zone of rapid change in mineral composition and density, occurring between 410 km and 660 km depth.

2. Lower Mantle: This is the layer below the transition zone, extending from 660 km to the outer core boundary at around 2,890 km. The lower mantle is predominantly solid and has a denser composition than the upper mantle.

It's important to note that the lower mantle is still very hot and under immense pressure, making it behave like a very viscous fluid over long periods.