This is some nasty old dryed grease gunk from this 80's Univega Nuovo Sport road bike I'm restoring and it is just a caked up mess. The top 2 photos you'll see the before and after photos of a bottom bracket cup and bearings that are just sludged up with rotten grease.
The bottom bracket is a little spindle that turns your crank arms when you pedal and is an important in getting the most efficiency out of your bike.
Let me put it his way. It's a lot easier to pedal when you're not doing it through 30 years of old tar.
Also, a lot of times you'll have bikes that are super squeaky when you pedal, those ones have run dry. In the Texas heat grease has a tendency to melt out of a bike and then you're dealing with metal on metal inefficient friction.
The bottom left photo is the inside of the hub of a 30 year old bike that was never serviced.
The hub is the very center of the bike wheel and the bearings inside it are what makes the wheel spin. it's what your fork rests on and once again this is an area where you want a slick and greasy situation in order to get the most out of your bicycle!
It's great to find a cherry bicycle that's been sitting in a garage but if it's not serviced properly it's missing out on its potential.