compare/contrast Spark with Cascading

[Philip Ogren]

My team is investigating a number of technologies in the Big Data 
space.  A team member recently got turned on to Cascading 
<http://www.cascading.org/about-cascading/> as an application layer for 
orchestrating complex workflows/scenarios. He asked me if Spark had an 
"application layer"?  My initial reaction is "no" that Spark would not 
have a separate orchestration/application layer.  Instead, the core 
Spark API (along with Streaming) would compete directly with Cascading 
for this kind of functionality and that the two would not likely be all 
that complementary.  I realize that I am exposing my ignorance here and 
could be way off.  Is there anyone who knows a bit about both of these 
technologies who could speak to this in broad strokes?

Thanks!
Philip